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Undifferentiated carcinoma metastatic to the bowel is uncommon in surgical pathology practice and might be confused with primary gastrointestinal carcinoma, melanoma, lymphoma, and others. We present 14 cases of uni- (n = 9) or multifocal (n = 5) undifferentiated large cell/rhabdoid carcinoma presenting in the bowel of patients with concurrent (n = 9) or recent (diagnosed 1 to 25 months earlier; median, 4) non-small cell lung cancer (NSCLC). Patients were 6 females and 8 males, aged 52 to 85 years. Primary NSCLC was verified histologically in 10 cases and by imaging in 4. The undifferentiated histology was present in the lung biopsy in 4/10 patients (as sole pattern in 3 and combined with adenocarcinoma in 1) and was limited to the intestinal metastases in the remainder. PDL1 was strongly expressed in 7/9 cases (CPS: 41 to 100). Loss of at least one SWI/SNF subunit was detected in 7/13 cases (54%). SMARCA2 loss (n = 6) was most frequent and was combined with SMARCA4 loss in one case. PBRM1 loss was observed in one tumor. Successful molecular testing of 11 cases revealed BRAF mutations in 4 (3 were non-V600E variants), KRAS mutations in 3, and wildtype in 4. None had EGFR mutations. Analysis of 4 paired samples revealed concordant KRAS (2) and BRAF (1) mutations or wildtype (1). Our study indicates that undifferentiated carcinoma within the intestines of patients with concurrent/recent NSCLC represents dedifferentiated metastasis from the NSCLC. Recognition of this unusual presentation is cardinal to avoid misdiagnosis with inappropriate therapeutic and prognostic implications., (© 2021. The Author(s).)

Primary gastrointestinal liposarcoma is rare, and information regarding this entity is largely based on single case studies. We report on 8 patients with primary liposarcoma of the gastrointestinal tract and review the pertinent literature. The cohort includes 6 men and 2 women who ranged in age from 51 to 81 years (median 68.5). Two tumors arose in the stomach, 4 in the small intestine, and 2 in the large intestine. Tumors ranged in size from 2.5 to 14.5 cm (median 7 cm), originated in the submucosa or muscularis propria of the intestinal wall, and frequently protruded into the bowel lumen, resulting in mucosal ulceration and luminal obstruction. Six tumors were dedifferentiated liposarcomas, and 2 were well-differentiated liposarcoma. Surgical excision was performed on all tumors except for 1 case of dedifferentiated liposarcoma. On follow-up, 1 patient with dedifferentiated liposarcoma developed a lytic sacral lesion suspicious for metastasis 4 months after resection of the primary, and another underwent marginal resection and presented with recurrence 4 years later, had tumor re-resection, and was considered disease-free at 6 weeks postsurgery. A third patient with dedifferentiated liposarcoma was alive with unknown disease status at 17 months following surgery, and another patient with dedifferentiated liposarcoma was alive without evidence of disease at 30 months following surgery. No follow-up information on the remaining patients is available. Overall, liposarcomas of the intestinal tract are most frequently high-grade dedifferentiated tumors that are biologically aggressive and require surgical excision with widely negative margins to help reduce the risk of local recurrence and dissemination. Important in the differential diagnosis is malignant gastrointestinal stromal tumor. Care must be taken not to misdiagnose one entity for the other because the correct diagnosis carries important therapeutic implications., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Small bowel neuroendocrine tumors (SBNETs) are rare cancers originating from enterochromaffin cells of the gut. Research in this field has been limited because very few patient derived SBNET cell lines have been generated. Well-differentiated SBNET cells are slow growing and are hard to propagate. The few cell lines that have been established are not readily available, and after time in culture may not continue to express characteristics of NET cells. Generating new cell lines could take many years since SBNET cells have a long doubling time and many enrichment steps are needed in order to eliminate the rapidly dividing cancer-associated fibroblasts. To overcome these limitations, we have developed a protocol to culture SBNET cells from surgically removed tumors as spheroids in extracellular matrix (ECM). The ECM forms a 3-dimensional matrix that encapsulates SBNET cells and mimics the tumor micro-environment for allowing SBNET cells to grow. Here, we characterized the growth rate of SBNET spheroids and described methods to identify SBNET markers using immunofluorescence microscopy and immunohistochemistry to confirm that the spheroids are neuroendocrine tumor cells. In addition, we used SBNET spheroids for testing the cytotoxicity of rapamycin.

A major problem in neuroendocrine pathology is the identification and separation of aggressive low-grade neuroendocrine tumors (LGNETs) from those with a benign or more indolent behavior. Presently there are no known morphologic or molecular parameters which can predict how localized LGNETs will behave. The phosphatase and tensin homolog (PTEN) gene negatively regulates the PI3K-AKT-mTOR pathway and inhibits neoplastic cell survival and proliferation and has recently been identified as a neuroendocrine tumor differentiation marker. We hypothesized loss of PTEN may also identify LGNETs that demonstrate aggressive behavior. We studied PTEN and pAKT expression in 18 LGNETs using specific monoclonal antibodies. Follow up was obtained for a minimum of five years on all patients. 8/18 cases had strong PTEN expression and showed no evidence of disease on >5 years follow-up. 10 cases demonstrated loss of PTEN expression; 9/10 had positive pAKT expression, and 7/9 had recurrence and/or metastases. Lung and appendiceal LGNETs uniformly had high PTEN expression and a markedly better prognosis than their gastroenteropancreatic (GEP) counterparts. Loss of PTEN correlated significantly with the positive expression of pAKT ( P =0.0027) and aggressive behavior of LGNETs ( p =0.0002). Loss of PTEN and increased pAKT correlated with the metastatic potential of LGNETs ( p =0.0011 and 0.0248 respectively). Loss of PTEN and increased pAKT expression distinguishes aggressive LGNETs from those with more indolent behavior., (© 2018 by the Association of Clinical Scientists, Inc.)

Background: Small intestinal neuroendocrine tumors (SI-NETs) originate from enterochromaffin cells scattered in the intestinal mucosa of the ileum and jejunum. Loss of one copy of chromosome 18 is the most frequent observed aberration in primary tumors and metastases. The aim of this study was to investigate possible involvement of 5-hydroxymethylcytosine (5hmC), TET1 and TET2 in SI-NETs., Methods: The analysis was conducted using 40 primary tumors and corresponding 47 metastases. The level of 5hmC, TET1 and TET2 was analyzed by DNA immune-dot blot assay and immunohistochemistry. Other methods included a colony forming assay, western blotting analysis, and quantitative bisulfite pyrosequencing analysis. The effect of the exportin-1 nuclear transport machinery inhibitors on cell proliferation and apoptosis was also explored using two SI-NET cell lines., Results: Variable levels of 5hmC and a mosaic staining appearance with a mixture of positive and negative cell nuclei, regardless of cell number and staining strength, was observed overall both in primary tumors and metastases. Similarly aberrant staining pattern was observed for TET1 and TET2. In a number of tumors (15/32) mosaic pattern together with areas of negative staining was also observed for TET1. Abolished expression of TET1 in the tumors did not seem to involve hypermethylation of the TET1 promoter region. Overexpression of TET1 in a colony forming assay supported a function as cell growth regulator. In contrast to 5hmC and TET1, TET2 was also observed in the cytoplasm of all the analyzed SI-NETs regardless of nuclear localization. Treatment of CNDT2.5 and KRJ-I cells with the exportin-1 (XPO1/CRM1) inhibitor, leptomycin B, induced reduction in the cytoplasm and nuclear retention of TET2. Aberrant partitioning of TET2 from the nucleus to the cytoplasm seemed therefore to involve the exportin-1 nuclear transport machinery. Reduced cell proliferation and induction of apoptosis were observed after treatment of CNDT2.5 and KRJ-I cells with leptomycin B or KPT-330 (selinexor)., Conclusions: SI-NETs are epigenetically dysregulated at the level of 5-hydroxymethylcytosine/ TET1/TET2. We suggest that KPT-330/selinexor or future developments should be considered and evaluated for single treatment of patients with SI-NET disease and also in combinations with somatostatin analogues, peptide receptor radiotherapy, or everolimus.

Neural lesions occur uncommonly in the gastroenteropancreaticobiliary tract. However, due to the growing number of screening colonoscopy procedures, polypoid neural lesions of the colon are being recognised increasingly and range from benign tumours to high-grade malignant neoplasms. Morphological variability of neural tumours can be wide, although some entities share pathological features, and, as such, these lesions can be diagnostically challenging. We review the spectrum of pathology of neural tumours in the gastroenteropancreaticobiliary tract, with the goal of providing a practical approach for practising surgical pathologists., Competing Interests: Competing interests: None declared., (© Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.)

Background: The neuronal intermediate filament alpha-internexin (α-internexin) is a cytoskeleton protein which is involved in the tumor initiation and progression. In this study, we examined the expression and prognosis value of α-internexin in gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs)., Methods: α-internexin was detected with immunohistochemical staining in 286 tumor specimens from patients with GEP-NENs. Methylation status of α-internexin was evaluated by bisulfite genomic sequencing. We assessed the prognostic value of α-internexin and its correlation with relevant clinicalpathological characteristics., Results: The reduced/loss of expression rate of α-internexin in GEP-NEN was 73.4% (210/286), while the positive expression rate was 26.6% (76/286). The difference of α-internexin deficiency was not statistically significant between gastrointestinal NENs (GI-NENs) and pancreatic NENs (pNENs). However, we found significant difference of reduced/loss of α-internexin expression among different sites of GI-NENs (χ 2  = 43.470, P < 0.001). The reduced/loss of expression of α-internexin was significantly associated with poorly differentiation (P < 0.001) and advanced tumor stage (P < 0.001). Univariate analyses showed that reduced/loss of expression of α-internexin predicted worse overall survival (OS) in GEP-NEN patients (P < 0.001), especially in subtype of GI-NENs (P < 0.001). However, in multivariable regression analysis, α-internexin expression was not an independent prognostic factor. The hypermethylation of α-internexin gene was significantly correlated with protein deficiency in GI-NENs, but not in pNENs. Hypermethylation of several CpG sites was significantly associated with poorly differentiated and advanced stage (P values range from 0.018 to 0.044). However, the methylation status of α-internexin was not associated with patient OS., Conclusions: The expression of α-internexin was highly heterougeneous in different sites of GEP-NENs. The reduced/loss of expression of α-internexin was closely related to tumors with aggressiveness and patient's adverse prognosis. The hypermethylation of the regulatory region examined may be an important epigenetic regulation mechanism of α-internexin deficiency in subtype of GI-NENs.

Some case reports of neuroendocrine tumors and neuroendocrine carcinoma associated with ulcerative colitis (UC) have been published. Most neuroendocrine tumor cases are small lesions corresponding to microcarcinoids (MCs). However, published case reports have presented findings of MCs as single-case reports. Thus, the frequency of MCs is still unclear. In this study, we described the clinical and morphological features of 14 cases of UC-associated MCs and estimated the frequency of MCs. Consecutive patients with UC who underwent complete removal of the large intestine were assessed, and 135 patients were selected. Of the 135 cases, 14 cases (10.4%) in which MC lesions were observed histologically were classified as the MC group, and the remaining 121 cases were classified as the control group. Seven cases in the MC group (50%) exhibited colitic cancer. No cases in either group had distinct carcinoid tumors. All MC lesions were located in the rectum, and the sizes ranged from 0.1 to 5.5 mm. Eight cases (57%) had multiple MC lesions. The frequency of MCs in UC was estimated to be 10.4%. Most cases of MC were quite unlikely to develop into clinically distinct carcinoid tumors. Thus, when MC lesions remain microscopic, they may not represent true neoplasms, which require immediate surgical resection. Because MC often arose in cases with UC complicated by dysplasia or cancer, patients with UC whose rectal biopsies reveal MC may be at high risk of colitic cancer., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Purpose: To re-evaluate and compare CT features of neuroendocrine liver metastases (NLM) from pancreatic (p) and enteric (e) gastroenteropancreatic (GEP) tumours., Material and Methods: From 2006-2013, all patients with proven GEP-neuroendocrine tumours (NETs) with at least one NLM, no previous treatment were included. On unenhanced, arterial and portal phases, NLMs were characterized as hypo-, iso- or hyperattenuating in consensus by 2 radiologists blinded to clinical data. Enhancement patterns (EP) corresponded to the combination of arterial/portal CT attenuation., Results: 78 patients (43 men, 55%, mean 56±13 yo) and 559NLMs were analyzed. pNLMs were more frequently hypoattenuating on unenhanced CT than eNLMs (72% vs. 57%, p<0.001). 70% of the lesions were hypervascular with no significant difference between pNLMs and eNLMs (p=0.32). eNLMs were more frequently hypoattenuating on portal phase than pNLMs (88% vs. 56%, p<0.001). eNLMs were more frequently hyper/hypo than pNLMs (56% vs. 28%, p<0.001). pNLMs were more frequently hyper/iso than eNLMs (33% vs. 8%, p<0.001). Other NLMs showed various patterns, including hypo/hypo in 12%., Conclusion: Most NLMs of GEP tumours are hypervascular but the enhancement pattern on multiphasic CT depends on the primary tumour. These differences are helpful when the primary tumour has not been diagnosed., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Background: An accurate diagnosis of cancer of Müllerian origin is required before the initiation of treatment. An overlap in clinical presentation and cytological, histological, or imaging studies with other nongynecological tumors does occur. Therefore, immunocytochemistry markers are used to determine tumor origin. Human epididymis protein 4 (HE4) is overexpressed in tissue of epithelial ovarian cancer (EOC). It has shown to be a sensitive and specific serum marker for EOC and to be of value for the differentiation between EOC and ovarian metastases of gastrointestinal origin. The objective of the current study was to evaluate HE4 immunocytochemistry in malignant ascites for differentiation between cancer of Müllerian origin, including EOC, and adenocarcinomas of the gastrointestinal tract., Methods: Cytological specimens of 115 different adenocarcinomas (45 EOCs, 46 cases of gastric cancer, and 24 cases of colorectal cancer) were stained for HE4, paired box 8 (PAX8), and other specific markers., Results: 91% of the ascites samples from patients with EOC stained for both HE4 and PAX8. The 4 samples without HE4 staining were a clear cell carcinoma, a low-grade serous adenocarcinoma, an undifferentiated adenocarcinoma, and a neuroendocrine carcinoma. All high-grade serous adenocarcinomas (n = 37, 100%) stained with HE4, compared with 94% that stained positively for PAX8. In cases of gastric or colorectal cancer, 25% and 21% of cases, respectively, stained positive for HE4. No PAX8 staining was observed in colorectal or gastric adenocarcinomas., Conclusions: HE4 staining in ascites is feasible and appears to have a high sensitivity for high-grade serous ovarian cancer. HE4 is a useful addition to the current panel of immunocytochemistry markers for the diagnosis of EOC and for differentiation with gastrointestinal adenocarcinomas. Cancer Cytopathol 2017;125:197-204. © 2016 American Cancer Society., (© 2017 American Cancer Society.)

Purpose: The primary cilium is a solitary, sensory, immotile microtubule-based structure that arises from the centrosome and is projected from the surface of most human cell types. It has been hypothesized that primary cilia could serve as a tumor suppressor organelle. The objective of this pilot study was to investigate the presence and frequency of primary cilia in cells of small bowel and colorectal adenocarcinoma and to evaluate the prognostic significance of their frequency., Methods: The presence of primary cilia in cells in samples of small bowel (8 patients) and colorectal adenocarcinoma (32 patients) was evaluated. The primary cilia of cells were immunofluorescently labeled using primary monoclonal anti-acetylated agr;-tubulin antibody and cell nuclei were labeled using DAPI., Results: Primary cilia were identified in all examined specimens. The median frequency of primary cilia was 0.49% in cells of small bowel cancer and 0.22% in cells in colorectal cancer. Overall survival according to frequency of primary cilia in all intestinal adenocarcinomas was significantly longer in patients with higher frequency (≥ 0.187) than in patients with lower frequency of primary cilia (< 0.187) in univariate analysis (p=0.007) and also in the Cox proportional hazard model (p=0.032). Overall survival according to frequency of primary cilia in colorectal adenocarcinoma was significantly longer in patients with higher frequency (≥ 0.187) than in patients with lower frequency of primary cilia (< 0.187) (p=0.028)., Conclusions: The present pilot study provides the first evidence of the prognostic significance of the frequency of primary cilia in small bowel and colorectal adenocarcinoma. Because of significantly higher median frequency of primary cilia in the rare small bowel adenocarcinoma than in the frequent colorectal adenocarcinoma (p<0.001), the results of this study support a potential role for primary cilia as a biomarker in these types of cancer.

This is the first report describing a case where prolonged, severe malabsorption from brown bowel syndrome progressed to multifocally spread small bowel adenocarcinoma. This case involves a female patient who was initially diagnosed with chronic jejunitis associated with primary diffuse lymphangiectasia at the age of 26 years. The course of the disease was clinically, endoscopically, and histologically followed for 21 years until her death at the age 47 due to multifocal, metastasizing adenocarcinoma of the small bowel. Multiple lipofuscin deposits (so-called brown bowel syndrome) and severe jejunitis were observed microscopically, and sections of the small bowel showed dense lymphoplasmacytic infiltration of the lamina propria as well as blocked lymphatic vessels. After several decades, multifocal nests of adenocarcinoma cells and extensive, flat, neoplastic mucosal proliferations were found only in the small bowel, along with a loss of the mismatch repair protein MLH1 as a long-term consequence of chronic jejunitis with malabsorption. No evidence was found for hereditary nonpolyposis colon carcinoma syndrome. This article demonstrates for the first time multifocal carcinogenesis in the small bowel in a malabsorption syndrome in an enteritis-dysplasia-carcinoma sequence.

Special AT-rich sequence binding protein-2 (SATB2) is selectively expressed in the lower gastrointestinal tract mucosa and has been identified as a sensitive marker for colorectal adenocarcinomas. The goal of this study was to investigate the expression of SATB2 in well-differentiated neuroendocrine tumors to explore its potential as a diagnostic marker for hindgut well-differentiated neuroendocrine tumors. Immunohistochemical staining with a monoclonal antibody to SATB2 was performed on full tissue blocks in 167 well-differentiated neuroendocrine tumors of various origins. The staining was semi-quantitatively scored as 0 (no tumor cell staining), 1+ (1-25%), 2+ (26-50%), 3+ (51-75%) and 4+ (76-100%). Positive SATB2 staining was seen in 17% foregut (14/84, 12/66 primary and 2/18 metastatic), 12% midgut (3/22, 3/18 primary and 0/7 metastatic), and 90% hindgut (52/58, 44/49 primary and 8/9 metastatic) well differentiated neuroendocrine tumors. Most hindgut well-differentiated neuroendocrine tumors (41/58) showed 4+ staining. The specificity of SATB2 for foregut, midgut and hindgut well-differentiated neuroendocrine tumors was 34%, 54% and 84%, respectively. Our results indicate that SATB2 is a sensitive marker for hindgut well-differentiated neuroendocrine tumors though it is not entirely specific. SATB2 should be included in the immunohistochemical panel in working out metastatic well-differentiated neuroendocrine tumor of an unknown origin.

NKX6-1 is a homeobox transcription factor participating in the development and regulation of endocrine function of pancreatic islets. This study evaluated the potential use of NKX6-1 as a diagnostic marker for well-differentiated neuroendocrine tumors (WDNETs). In total, 178 primary and 26 metastatic WDNETs of different origins were analyzed through immunohistochemistry for NKX6-1, TTF-1, CDX2, ISL1, and polyclonal PAX8. NKX6-1 was expressed in 36 of the 44 (82%) primary pancreatic WDNETs, 12 of the 18 (67%) primary duodenal WDNETs, and rarely in pulmonary, gastric, and appendiceal WDNETs. The specificity of using NKX6-1 as a marker for pancreatic and duodenal WDNETs is 93%. Of the 26 metastatic WDNETs, NKX6-1 was expressed only in the tumors of pancreatic origin (sensitivity: 63%, specificity: 100%). The combinatorial use of NKX6-1, CDX2, TTF-1, and ISL1 distinguished WDNETs of different origins with high specificity. Our results indicated that the inclusion of NKX6-1 in an immunohistochemical panel will be beneficial for identifying the primary sites of WDNETs.

Phytosterol oxidation products (POPs) are constituents of the human diet. Definitive information on the toxic or biological effects of POPs is limited and in some cases contradictory. This study evaluates the cytotoxicity of four individual 7-ketophytosterol oxides, including 7-ketositosterol (7K-SI), 7-ketocampesterol (7K-CA), 7-ketobrassicasterol (7K-BR), 7-ketostigmasterol (7K-ST), and a mixture of 7-ketophytosterols (7K-MIX) toward a human intestinal carcinoma (HIC) cell line. Results showed that all tested compounds reduced cell proliferation in a dose-dependent manner; especially 7K-SI and 7K-CA exhibited higher activities. Both compounds increased early apoptotic cells and caused cell cycle arrest in the G1 phase with cell accumulation in the S phase. No evidence of cell death was observed induced by 7K-ST and 7K-MIX. Furthermore, 7K-SI, 7K-CA, and 7K-BR induced apoptosis by enhancing caspase-3 activity and the modulatory effects of Bcl-2, while 7K-ST and 7K-MIX did not involve caspase-3 activation and Bcl-2 down-regulation.

Early detection of colonic polyps can prevent up to 90% of colorectal cancer deaths. Conventional colonoscopy readily detects the majority of premalignant lesions, which exhibit raised morphology. However, lesions that are flat and depressed are often undetected using this method. Therefore, there is a need for molecular-based contrast agents to improve detection rates over conventional colonoscopy. We evaluated a quenched fluorescent activity-based probe (qABP; BMV109) that targets multiple cysteine cathepsins that are overexpressed in intestinal dysplasia in a genetic model of spontaneous intestinal polyp formation and in a chemically induced model of colorectal carcinoma. We found that the qABP selectively targets cysteine cathepsins, resulting in high sensitivity and specificity for intestinal tumors in mice and humans. Additionally, the qABP can be administered by either intravenous injection or by local delivery to the colon, making it a highly valuable tool for improved detection of colorectal lesions using fluorescence-guided colonoscopy., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

Background/aims: Gastroenteropancreatic neuroendocrine tumors (GEP-NETs) are a unique subgroup of tumors in the digestive system but with great clinical heterogeneity. The information on clinical characteristics and prognostic factors of Chinese patients is rather limited., Methodology: We retrospectively analyzed the clinical features, prognostic factors of this disease in a consecutive cohort (N=294) between January 2007 and December 2012., Results: Functioning tumors accounted for 9.2%. Rectum was the most predominant GEP-NETs locations. Abdominal pain occurred in 46.5% patients which was the most common initial symptom. G1, G2 and G3 tumors accounted for 41.5%, 34.7% and 23.8%, respectively. Endoscopy provided the highest detection rate of 95.7%. Consistence between endoscopic ultrasound guided fine needle aspiration biopsy (EUS-FNAB) and surgically obtained histological Ki-67 index was 36.4%. Serum CgA test showed a 80.0% consistence with the tissue biopsy. The median follow up duration was 2.8 years (0.02-5.90 years), the median survival was 4.8 years, overall 5-year survival rate was 69.6%. We found colonic localization, tumor size larger than 20 mm, G3 tumor and metastasis were associated with worse outcome (p<0.05)., Conclusion: We found both consistence and differences in GEP-NETs characteristics between our study and previous reports.

Background/aims: To review our treatment experience of gastrointestinal stromal tumors (GISTs) of the upper gastrointestinal tract and identify the prognostic factors that influence tumor recurrence., Methodology: Data of 46 consecutive patients with upper GI GISTs who underwent surgery from 1988 to 2011 were reviewed. The overall and disease-free survival rates and influence of clinicopathologic variables on disease-free survival rate were evaluated., Results: The median age was 64 years (range, 20-86 years). R0 resections were performed in 43 (93.5%) patients. With a median follow-up time of 33 months (1-275 months), there were 5 (10.9%) recurrences and 2 mortalities in the high-risk group. The overall survival and recurrence-free survival rates at 5 years were 92.1% and 84.6%, respectively. Male gender, tumor size of >10 cm, high numbers of mitotic figures, R1 resection, high risk according to the Joensuu criteria, and a Ki-67 index of >10% were associated with a poor prognosis., Conclusions: Surgical resection of low- and intermediate-risk GISTs has excellent results. High counts of mitotic figures, male gender, incomplete resection, large tumor size, and a high Ki-67 index are associated with a poor prognosis.

Primary malignant tumors of the small intestine are rare, comprising less than 2% of all gastrointestinal tumors. An 85-year-old woman was admitted with fever of 40 °C and marked abdominal distension. Her medical history was unremarkable, but blood examination showed elevated inflammatory markers. Abdominal computed tomography showed a giant tumor with central necrosis, extending from the epigastrium to the pelvic cavity. Giant gastrointestinal stromal tumor of the small intestine communicating with the gastrointestinal tract or with superimposed infection was suspected. Because no improvement occurred in response to antibiotics, surgery was performed. Laparotomy revealed giant hemorrhagic tumor adherent to the small intestine and occupying the peritoneal cavity. The giant tumor was a solid tumor weighing 3490 g, measuring 24 cm × 17.5 cm × 18 cm and showing marked necrosis. Histologically, the tumor comprised spindle-shaped cells with anaplastic large nuclei. Immunohistochemical studies showed tumor cells positive for vimentin, CD31, and factor VIII-related antigen, but negative for c-kit and CD34. Angiosarcoma was diagnosed. Although no postoperative complications occurred, the patient experienced enlargement of multiple metastatic tumors in the abdominal cavity and died 42 d postoperatively. The prognosis of small intestinal angiosarcoma is very poor, even after volume-reducing palliative surgery.

Ovarian cystadenocarcinoma is characterized by marked heterogeneity and may be composed of an admixture of histologic growth patterns, including acinar, papillary and solid. In the present study, a case of isolated small intestine metastasis of ovarian papillary cystadenocarcinoma was reported. A 7-year-old female mixed-breed dog presented with a mass in the left upper quadrant with progressive enlargement of the abdomen, periodic bloody discharge from the vulva and incontinence. The tumor was histologically characterized by the presence of cysts and proliferation of papillae, both lined by single- or multi-layered pleomorphic epithelial cells. Furthermore, the mass was composed by intense cellular and nuclear pleomorphism and numerous mitotic figures. These findings indicate a tumor of high-grade malignancy with infiterative tumor cells resembling the papillary ovarian tumor in the serosal surface of the small intestine along with an intact serosa. Immunohistochemically, tumor was positive for CK7 and negative immunoreactivity for CK20. The histopathologic features coupled with the CK7 immunoreactivity led to a diagnosis of high grade ovarian papillary cystadenocarcinoma. To the best of our knowledge, this is the first case of small intestine serousal surface metastasis from ovarian papillary cystadenocarcinoma.

Aims: Due to the rarity of small intestine adenocarcinoma (SIAC), estimating the prognosis for patients with surgically resected SIAC is difficult. Overexpression of S100A4 has been linked to worse patient survival in several malignant neoplasms, but its significance in SIAC has not been determined., Methods: S100A4 protein expression was assessed in 197 surgically resected SIAC cases and compared with clinicopathological factors, including patient survival., Results: A progressive increase in S100A4 labelling was observed in normal intestinal epithelium, adenoma and adenocarcinoma (p<0.001), and 50 SIAC cases (26.2%) showed strong S100A4 expression. Patients with SIAC with strong S100A4 expression had a higher pT classification (p=0.05), as well as increased lymph node metastasis (p=0.009) and perineural invasion (p=0.002). Patients with SIAC with strong S100A4 expression had significantly worse survival (median survival, 21 months) than those with weak/no S100A4 expression (42.5 months) by univariable (p=0.04) and multivariable (p=0.01) analyses., Conclusions: S100A4 overexpression is observed in a subset of SIACs, is associated with advanced disease and can be used as a prognostic indicator of poor prognosis in patients with SIAC.

The epithelial-cell layer lining the two morphologically and functionally distinct segments of the mammalian intestinal tract, small intestine, and colon is constantly being renewed. This renewal is necessitated by a harsh lumen environment and is hypothesized to be driven by a small population of stem cells (SCs) that are believed to reside at the base of intestinal crypts. A lack of specific markers has hampered previous attempts to identify their exact location. We obtained tissue sections containing small intestine and colon crypts derived from normal (benign) or adenocarcinoma (AC) human intestine. The samples were floated onto BaF2 windows and analyzed using synchrotron radiation-based Fourier transform infrared microspectroscopy via an aperture size of 10 × 10 μm. Derived infrared (IR) spectral data was then analyzed using principal component analysis and/or linear discriminant analysis. Hypothesized cell types (as a function of aperture location along the length of individual crypts) within benign crypts were classed based on exploratory unsupervised IR spectral point clustering. Scores plots derived from individual small intestine crypts consistently generated one or two distinct spectra that clustered away from the remaining cell categories; these were retrospectively classed as "distinct base region" spectra. In these plots, a clear progression of locations along crypt lengths designated as from putative stem cells (SCs) to transit-amplifying (TA) cells to terminally differentiated (TD) cells was observed in benign small intestine and colon crypts. This progression of spectral points was crypt specific, pointing away from a unifying cell lineage model in human intestinal crypts. On comparison of AC-derived spectra versus corresponding benign, a subpopulation of AC-derived spectra suggested a putative SC-like spectral fingerprint; remaining IR spectra were classed as exhibiting TA cell-like or TD cell-like spectral characteristics. These observations could point to a cancer SC phenotype; an approach capable of identifying their in situ location has enormous therapeutic applications.

Leiomyomas (LMs) of the gastrointestinal tract arise within the muscularis mucosae (superficial) and muscularis propria (deep). There are isolated reports of KIT-positive cells, presumed interstitial cells of Cajal (ICCs), within gastrointestinal LMs. We have encountered esophageal LMs with a high proportion of KIT-positive and DOG1-positive spindle-shaped cells, an appearance that mimicked gastrointestinal stromal tumor. Our aim was to explore the prevalence of ICCs in LMs of the gastrointestinal tract and the etiopathogenic significance of these cells in this benign neoplasm. We identified 34 esophageal LMs (28 deep, 6 superficial), 8 gastric LMs, and 5 small-bowel LMs (all lesions in muscularis propria). We performed immunohistochemical staining studies for desmin, DOG1, and KIT on these neoplasms. We also evaluated 12 superficial colonic LMs. ICCs were distinguished from mast cells on the basis of morphology (elongated and occasionally branching spindle-shaped cells) and the presence of DOG1 reactivity. Four cases were screened for mutations in PDGFRA exons 12, 14, and 18 and KIT exons 9, 11, 13, and 17. ICCs were identified in all deep esophageal LMs and constituted an average of 20% of the lesional cells; focally, these cells comprised >50% of cells. The density of these cells was significantly higher than the background muscularis propria, and hyperplasia of ICCs was not identified in the adjacent muscle. ICCs were identified in 6 of 8 gastric LMs and 1 of 5 small-bowel LMs and were entirely absent in all superficial esophageal and colonic/rectal LMs. There were no mutations in KIT or PDGFRA. ICCs are universally present in deep esophageal LMs, and thus these neoplasms could be mistaken for gastrointestinal stromal tumors, particularly on biopsy samples, an error associated with adverse clinical consequences. ICCs are also identified in gastric and intestinal LMs, albeit in a smaller proportion of cases. Colonization and hyperplasia by non-neoplastic ICCs likely account for this phenomenon.

Background/aims: We re-evaluated the clinical, histopathological and immunohistochemical features of neuroendocrine tumors (NETs) diagnosed in our pathology laboratory between 2004 and 2012 and re-classified them according to the WHO-2000 and WHO-2010 criteria., Methodology: The study included NET samples of 106 patients having gastroenteropancreatic and hepatobiliary tumors. The histopathological findings were re-assessed. The cases were re-appraised based on the WHO-2000 and WHO-2010 criteria. The association between survival and Ki-67 index was analysed., Results: The most frequent localization was the stomach. The average tumor size was 3.0±4.1 cm. Differentiation was poor in 17 cases (16.0%). Lymphovascular invasion was detected in 16.1% (n = 17) and necrosis was identified in 15.1% (n = 16). The average number of Ki-67 was 9.1±19.9. Ki-67 measurements were significantly higher in patients who died compared to those who survived (p <0.01). In ROC analysis, the cut-off point for Ki-67 was 5., Conclusions: Our study is a single-center study comprising patients from Turkey for a period of 8 years. We found that the most frequent localization is the stomach. This ratio is associated with common use of endoscopy in our center. The specimens were re-evaluated according to the WHO-2000 and WHO-2010 classification systems the data and terminology have been updated.

Aims: Microcarcinoids refer to microscopic nests of monotonous cells with endocrine and squamoid features. Their peculiar morphology can appear infiltrative with a desmoplastic-like background, raising concerns for an infiltrating adenocarcinoma. To further characterise microcarcinoids, we undertook a prospective clinicopathological study., Methods: 11 specimens originating from five men and six women (average age=58.9 years) were prospectively collected from December 2004 to December 2011., Results: Microcarcinoids were most commonly identified in high-risk adenomas (size ≥10 mm (n=10), villous components (n=8) and/or high-grade dysplasia (n=4)). All polyps had mucosal prolapse and four displayed background fibrosis reminiscent of desmoplasia. The microcarcinoid component was most often multifocal (n=7) within the individual polyp and extended over an average length of 3.9 mm. The individual microcarcinoid cells were cuboidal with abundant eosinophilic cytoplasm. All cases had monotonous nuclei which lacked pleomorphism, hyperchromasia and mitotic activity. All available microcarcinoids were β-catenin and synaptophysin reactive and non-reactive for chromogranin and p53 with a negligible Ki-67 proliferation index (<2%). In addition, the microcarcinoids were variably reactive for p63 and/or CK 5/6, thereby demonstrating focal squamoid features. Two of the study cases were submitted with a concern for invasive carcinoma. Clinical information was available in 10 patients with up to 24 months of follow-up: all patients are alive and well and no subsequent malignancy has been reported., Conclusions: Awareness of this unique morphology is important to avoid overdiagnosing microcarcinoids as invasive adenocarcinoma. Moreover, this immunohistochemical panel can be helpful in discriminating microcarcinoids from its malignant mimic in challenging cases.

Background: MET is a proto-oncogene with its copy number (CN) alterations been reported in some cancers, but not in primary intestinal diffuse large B-cell lymphoma (PI-DLBL) yet., Methods: In this retrospective study, we performed histology and chart reviews, immunohistochemistry and quantitative polymerase chain reaction for MET CN alterations on 28 surgically resected PI-DLBLs., Results: There were 12 men and 16 women with a median age of 70 and a mean follow-up of 32 months. The median MET CN was 2.20 (range, 1.04 to 3.35). CN gain was observed in 11 cases, including 5 with CN greater than 3. Nine patients (32%) had diploid CN and eight (29%) with CN loss. Patients with gain or diploid CN showed significantly worse prognosis (P = 0.046) than those with CN loss. Furthermore, MET CN greater than 3 was associated with an adverse outcome (P = 0.003). Intestinal perforation at presentation was the sole clinicopathological factor associated with a poor prognosis (P = 0.004) and perforation was correlated with CN greater than 3 (P = 0.002)., Conclusions: Our finding of MET CN gain as a poor prognostic factor in PI-DLBL patients might serve as the rationale for targeting MET signaling pathway in the treatment of these patients.

Objective: The insulin-like growth factor (IGF) system has been known to play a critical role in tumor development and progression in many human cancers. However, the role of the IGF system in small intestinal carcinoma (SIC) has not been studied yet., Methods: We evaluated the expression of IGF1 and IGF1 receptor (IFG1R) in a total of 194 cases of SIC., Results: IGF1 expression was associated with well/moderate differentiation, better survival, lower pT, lower stage and no lymph node metastasis. IGF1R was more diffusely and strongly expressed in tumors with lower pT and lower stage., Conclusions: IGF1 and IGF1R expression is associated with favorable clinicopathologic parameters and may involve early carcinogenesis of SICs. Target therapy for the IGF1R signaling pathway may not have a major therapeutic role in treating SIC., (Copyright © 2013 S. Karger AG, Basel.)

Pathologic grading for prognostic stratification of neuroendocrine tumors (NETs) is critical but presents a challenging interpretive dilemma. Tumor cell proliferative rate is an important factor in the determination of prognosis, and immunohistochemical analysis with Ki67 is becoming more widely used to quantify the proliferative rate. However, Ki67 assessment has limitations due to lack of uniformity and consistency in quantification. These limitations are accentuated in well-differentiated NETs, as differences in the range of 1% to 5% can alter tumor grade, with potential implications for treatment. We therefore performed a concordance study to assess different Ki67 quantification techniques including: (a) digital image analysis (DIA); (b) manual counting (MC) of >2000 cells; and (c) "eyeballed" estimate (EE) of labeling percentage by pathologists (n=18), including individuals experienced in evaluating Ki67 labeling as well as others who had little prior experience assessing Ki67 percentages. Forty-five Ki67 images were selected and analyzed using the 3 methods. On the basis of the recommendations of the World health Organization (WHO) for grading NETs, MC of 2000 cells was used as the "gold standard" reference against which the other techniques were compared. Three images were presented twice, the second being inverted, to assess intraobserver consistency. Statistical analyses were performed to evaluate: (a) the concordance between methods; (b) intraobserver and interobserver consistency; and (c) correlation of NET grades on the basis of Ki67 scores by EE versus the gold standard. Agreement between scores was assessed by intraclass correlation (ICC). DIA and MC were highly concordant (ICC=0.98). The ICC between DIA and the mean EE of all observers was 0.88. However, there was discordance among individual observers on all cases quantified by EE (ICC=0.13). The ICC for intraobserver consistency was 0.39±0.26. With Ki67 in the ranges of <1%, 2% to 3%, and >20%, the mean of Ki67 by EE was, respectively, 93%±2%, 55%±7%, and 55%±15% correct against the gold standard. The κ statistics for EE exhibited low agreement (κ=0.24; 95% confidence interval, 0.23-0.25) for all WHO NET grades. Incorrect assessment by EE resulted in upgrading of all WHO G1 group tumors (n=14); in the WHO G2 group, downgrading of 41% cases occurred (n=11) when Ki67 was <5% (by DIA or MC), and upgrading of 59% cases occurred (n=16) when Ki67 was >5%. We conclude that DIA and MC are the acceptable standards for Ki67 assessment. Given the inherent discordance in determining the grade, the use of an approximate EE of the Ki67-labeling index requires critical reevaluation, especially for NETs with a labeling index straddling the cut-points between grades. Consequently, determination of therapeutic strategies should be guided by an amalgamation of clinicopathologic characteristics, including but not limited to the Ki67 index.

Lymphangioma is a rare benign condition characterized by proliferation of lymphatic spaces. It is usually found in the head and neck of affected children. Lymphangioma of the small-bowel mesentery is rare, having been reported for less than 1% of all lymphangiomas. Importantly, it can cause fatal complications such as volvulus or involvement of the main branch of the mesenteric arteries, requiring emergency surgery. Moreover, the gross and histopathologic findings may resemble benign multicystic mesothelioma and lymphangiomyoma. Immunohistochemical study for factor VIII-related antigen, D2-40, calretinin and human melanoma black-45 (HMB-45) are essential for diagnosis. Factor VIII-related antigen and D2-40 are positive in lymphangioma but negative in benign multicystic mesothelioma. HMB-45 shows positive study in the smooth-muscle cells around the lymphatic spaces of the lymphangiomyoma. We report a case of small-bowel volvulus induced by mesenteric lymphangioma in a 2-year-and-9-mo-old boy who presented with rapid abdominal distension and vomiting. The abdominal computed tomography scan showed a multiseptated mass at the right lower quadrant with a whirl-like small-bowel dilatation, suggestive of a mesenteric cyst with midgut volvulus. The intraoperative findings revealed a huge, lobulated, yellowish pink, cystic mass measuring 20 cm × 20 cm × 10 cm, that was originated from the small bowel mesentery with small-bowel volvulus and small-bowel dilatation. Cut surface of the mass revealed multicystic spaces containing a milky white fluid. The patient underwent tumor removal with small-bowel resection and end-to-end anastomosis. Microscopic examination revealed that the cystic walls were lined with flat endothelial cells and comprised of smooth muscle in the walls. The flat endothelial cells were positive for factor VIII-related antigen and D2-40 but negative for calretinin. HMB-45 showed negative study in the smooth-muscle cells around the lymphatic spaces. Thus, the diagnosis was lymphangioma of the small bowel mesentery with associated small bowel volvulus.

Background/aims: The WHO 2010 grading system for gastroenteropancreatic neuroendocrine tumors(GEP-NETs) is used to evaluate the malignant potential without clinicopathological information. This study was conducted to examine whether the new index is superior to the previous WHO 2004 classification, e.g.for well-differentiated endocrine carcinoma (WEC),involving clinical information., Methodology: Between 2000 and 2011, 77 patients with sporadic GEP-NETs were treated at our institution and statistically estimated risk factors for overall survival (OS) were evaluated. Cox proportional hazards regression analyses were performed to estimate risk factors for OS., Results: Overall 1-, 3- and 5-year survival rates were 92.8%, 78.4% and 76.0%, respectively. Median OS was 551 days in WEC-patients (odds ratio (OR)for OS=13.1, 95% confidence interval (CI)=2.90-59.5;p=0.001). The median OS was 813 days in G3-patients as compared with 1885 days in G1/G2-patients(OR for OS= 2.64, p=0.002). Multivariate analyses according to baseline characteristics revealed WEC as independent risk factor (OR=9.06, p=0.01). WEC was the only predictor of prognosis with an area under the receiver operating characteristic curves of 0.78(p=0.001)., Conclusions: Clinical information was the best predictor for the prognosis of NETs.

Background/aims: Although primary small intestinal carcinoma (SIC) is morphologically similar to colorectal carcinoma and shares many of the genetic changes of carcinogenesis, little is known about the role of defective mismatch repair (MMR) genes involved in the SIC. The aim of this study is to investigate the role of defective MMR genes and correlation between clinicopathological factors and loss of MMR protein in SIC., Methodology: A total of 195 SIC cases were collected from 20 institutions in Korea and tissue microarrays (TMA) were made. The loss of expression of hMLH1, hMSH2 and hMSH6 was examined by immunohistochemistry (IHC)., Results: The loss of expression of hMLH1, hMSH2 and hMSH6 was identified in 25/193 (13.0%), 25/193 (13%) and 29/195 (15%), respectively. The loss of hMSH2 expression was associated with retroperitoneal seeding. Patients with loss of hMSH6 expression had a tendency to invade deeply and a higher frequency of pancreas invasion. The loss of hMSH6 expression was associated less frequently with peritumoral adenoma. There was no survival difference by MMR protein expression status., Conclusions: The loss of MMR protein was associated with some distinct clinicopathological features. MMR pathway seems to be major pathway in carcinogenesis of SICs. MMR defect seems to be related with sporadic-microsatellite instability (MSI).

Background: Gastrointestinal stromal tumors (GISTs) are rare tumors, accounting for 1-3% of all gastrointestinal malignancies; they are, however, the most common gastric and small bowel mesenchymal tumors. The length and relative inaccessibility of the small bowel have long constrained the diagnosis of GISTs mainly presenting with chronic or intermittent bleeding as the sole clinical manifestation., Aim: To report on the prevalence of small bowel GISTs in a prospectively recorded series of patients undergoing capsule endoscopy (CE)., Patients and Methods: Between 2001 and 2007 five hundred patients were referred to our endoscopy unit for small bowel evaluation with capsule endoscopy. We retrospectively evaluated all charts. The main indications for CE were obscure-occult or obscure-overt bleeding. Two hundred eighty-nine patients underwent CE for either obscure-occult or obscure-overt bleeding and 211 for other indications. Patient outcome and care processes were measured by follow-up telephone interviews and chart review. Statistical computations were performed using Fisher's exact test and Student's t-test., Results: CE identified a small bowel tumor in 20 patients (4.0%) and 9 tumors turned out to be GISTs (45.0%). Traditional endoscopic and radiological imaging failed to detect the GIST in all these cases. In one case a small bowel GIST was diagnosed by angiography and CE proved false negative. Overall, CE was able to diagnose a small bowel GIST in 9 out of 10 cases. All patients underwent surgical treatment and showed normalized hemoglobin levels at follow-up. The main limitation of this study is the small number of cases., Conclusions: CE is an effective and sensitive diagnostic device compared with conventional radiology and plays an important role in the algorithm for the diagnostic work-up of suspected small bowel tumors.

Background & Aims: Tumors that develop in patients with Crohn's disease tend be multifocal, so field cancerization (the replacement of normal cells with nondysplastic but tumorigenic clones) might contribute to intestinal carcinogenesis. We investigated patterns of tumor development from pretumor intestinal cell clones., Methods: We performed genetic analyses of multiple areas of intestine from 10 patients with Crohn's disease and intestinal neoplasia. Two patients had multifocal neoplasia; longitudinal sections were collected from 3 patients. Individual crypts were microdissected and genotyped; clonal dependency analysis was used to determine the order and timing of mutations that led to tumor development., Results: The same mutations in KRAS, CDKN2A(p16), and TP53 that were observed in neoplasias were also present in nontumor, nondysplastic, and dysplastic epithelium. In 2 patients, carcinogenic mutations were detected in nontumor epithelium 4 years before tumors developed. The same mutation (TP53 p.R248W) was detected at multiple sites along the entire length of the colon from 1 patient; it was the apparent founder mutation for synchronous tumors and multiple dysplastic areas. Disruption of TP53, CDKN2A, and KRAS were all seen as possible initial events in tumorigenesis; the sequence of mutations (the tumor development pathway) differed among lesions., Conclusions: Pretumor clones can grow extensively in the intestinal epithelium of patients with Crohn's disease. Segmental resections for neoplasia in patients with Crohn's disease might therefore leave residual pretumor disease, and dysplasia might be an unreliable biomarker for cancer risk. Characterization of the behavior of pretumor clones might be used to predict the development of intestinal neoplasia., (Copyright © 2012 AGA Institute. Published by Elsevier Inc. All rights reserved.)

There are few comprehensive studies of small intestinal malignancies. The author retrospectively reviewed 1,312 archival pathologic specimens of the small intestine in the last 10 years in our pathologic laboratory in search for malignant tumors of the small intestine. There were 22 cases (1.7%) of primary adenocarcinoma, 3 cases (0.2%) of primary squamous cell carcinoma, 6 cases (0.5%) of metastatic carcinoma, 6 cases (0.5%) of malignant lymphoma, 3 cases (0.2%) of carcinoid tumor, and 1 case (0.08%) of gastrointestinal stromal tumor (GIST). Of the 25 cases of primary adenocarcinoma and squamous cell carcinoma, 24 cases were located in the duodenum and 1 case in the ileum. The 22 cases of adenocarcinoma were classified into 7 well differentiated, 7 moderately differentiated, and 8 poorly differentiated adenocarcinomas. All the three squamous cell carcinomas were moderately differentiated ones with keratinization and intercellular bridges. In the 25 cases of carcinoma, immunoreactive p53 protein was present in 23 cases, and the Ki-67 labeling ranged from 40% to 95% with a mean of 76%. In the 6 cases of metastatic adenocarcinoma, the origin was ovary in 1 case, pancreas in 2 cases, gall bladder in 1 case, lung in 1 case, and colon in 1 case. In the 6 cases of lymphoma, 4 cases were diffuse large B-cell lymphomas and 2 cases were peripheral T-cell lymphomas. In the 3 cases of carcinoid tumor, all were typical carcinoids and immunohistochemically positive for at least one of neuroendocrine markers (chromogranin, synaptophysin, neuron specific enolase, and CD56). In the 1 case of GIST, the cell type is spindle and GIST cells were immunohistochemically positive for KIT and CD34. The histological risk was intermediate. Forty-one cases of small intestinal malignancies were reviewed histopathologically.

Aims and Background: Somatostatin receptor scintigraphy (SRS) is the standard method for the detection of somatostatin receptors (SSTRs). It is commonly used in gastroenteropancreatic neuroendocrine tumor (GEP-NET) staging, and represents the criterion of choice for treatment with somatostatin (SST) analogs. Immunohistochemistry (IHC) was reported as a reliable method for the detection of SSTRs with theoretically superior sensitivity over SRS., Methods and Study Design: We retrospectively analyzed the sensitivity and specificity of IHC in the detection of SSTRs in a cohort of consecutive patients with GEP-NETs attending our Institute from 1997 to 2007. IHC analysis was restricted to SSTR2 and SSTR5, and the results were interpreted according to two different scoring systems. SRS was used as the gold standard. Results. Forty-four patients were enrolled; 24 (55%) had foregut carcinoids, 9 (20%) midgut carcinoids, 2 (5%) hindgut carcinoids, and 9 (20%) had GEP-NETs of unknown primary sites. A high concordance rate between IHC and SRS was shown, irrespective of the IHC scoring system applied (73% and 70%). The sensitivity of IHC was 89.3% and 78.6% and the specificity 43.8% and 50%, depending on the scoring system used., Conclusions: Although SSTR2 was shown to be expressed by IHC in up to 50% of tumors not visualized by SRS, SRS still remains the method of choice in the diagnostic and therapeutic management of GEP-NETs. More pathological and clinical data are needed to properly understand the clinical relevance of immunohistochemical detection of SSTR expression in the absence of tumor uptake at SRS.

Background: Colorectal cancer is preventable by early detection and removal of precursor lesions. Central to early stages of colorectal neoplasia is activation of Wnt signaling, usually due to inactivation of the Apc tumor suppressor gene for which there is an established animal model, the Apc(Min) mouse. Immunodetection in stool of proteins up-regulated by aberrant Wnt signaling, within intestinal epithelial cells shed into the lumen, could be a rational approach to identify biomarkers of early intestinal neoplasia. Fem1b gene expression is up-regulated, following inactivation of Apc, in mouse intestinal epithelium., Methods: We initially screened pooled random stool samples by immunoblotting and found that we could detect, in Apc(Min) mice but not wild-type mice, a fragment of Fem1b protein with an antibody (Li-50) directed against an epitope near the middle of the protein, but not with antibodies directed against N-terminus or C-terminus epitopes. We then evaluated freshly voided individual stool samples collected on four consecutive days from four each of male and female Apc(Min) mice and their wild-type littermates., Results: The Fem1b antigen was detected with the Li-50 antibody in 15/16 samples from male Apc(Min) mice compared to 0/16 samples from male wild-type mice, and in 5/16 samples from female Apc(Min) mice compared to 0/16 samples from female wild-type mice., Conclusions: This study provides proof-of-principle that fragments of proteins, whose expression is increased by aberrant Wnt signaling early in intestinal neoplasia, can be immunodetected in stool. Excreted Fem1b protein fragments may be a useful biomarker for epithelial Wnt signaling and early intestinal neoplasia., (Copyright © 2010 Elsevier Ltd. All rights reserved.)

Intestinal T-cell lymphoma is a heterogenous group. These tumors differ in their association with enteropathy, intraepithelial or nonintraepithelial origin, primary or secondary involvement, and T-cell or natural killer-like T-cell immunophenotype. There are also nonneoplastic conditions, such as celiac disease, refractory sprue, and reactive T-cell infiltration that mimic intestinal T-cell lymphoma. Therefore, the differential diagnosis requires extensive morphologic, immunophenotypic, and molecular genetic studies. A subset of primary intestinal intraepithelial T-cell lymphoma has emerged in recent years that is distinguished from enteropathy-type T-cell lymphoma in terms of clinical presentation (nonenteropathic), morphology (monomorphic small to medium-sized cells), immunophenotype (CD3(-)CD8(+)CD56(+)), and cytogenetics. We report such a case with a unique immunophenotype (CD3(-), cytoplasmic CD3(+), CD4(-), CD8(+), CD5(-), CD7(+), CD16(-), CD56(+), CD57(-), CD103(+), T-cell intracellular antigen 1(+), and betaF1(+)) that is comparable to that of a newly identified subset of intraepithelial T cells. The tumor progressed rapidly and the patient died within 6 months after the onset of the disease. We recommend a large monoclonal antibody panel for the differential diagnosis of this heterogeneous group of T-cell lymphoma.

Background: In vitro models are indispensable study objects in the fields of cell and molecular biology, with advantages such as accessibility, homogeneity of the cell population, reproducibility, and growth rate. The Caco-2 cell line, originating from a colon carcinoma, is a widely used in vitro model for small intestinal epithelium. Cancer cells have an altered metabolism, making it difficult to infer their representativity for the tissue from which they are derived. This study was designed to compare the protein expression pattern of Caco-2 cells with the patterns of intestinal epithelial cells from human small and large intestine. HT-29 intestinal cells, Hep G2 liver cells and TE 671 muscle cells were included too, the latter two as negative controls., Results: Two-dimensional gel electrophoresis was performed on each tissue and cell line protein sample. Principal component and cluster analysis revealed that global expression of intestinal epithelial scrapings differed from that of intestinal epithelial cell lines. Since all cultured cell lines clustered together, this finding was ascribed to an adaptation of cells to culture conditions and their tumor origin, and responsible proteins were identified by mass spectrometry. When investigating the profiles of Caco-2 cells and small intestinal cells in detail, a considerable overlap was observed., Conclusion: Numerous proteins showed a similar expression in Caco-2 cells, HT-29 cells, and both the intestinal scrapings, of which some appear to be characteristic to human intestinal epithelium in vivo. In addition, several biologically significant proteins are expressed at comparable levels in Caco-2 cells and small intestinal scrapings, indicating the usability of this in vitro model. Caco-2 cells, however, appear to over-express as well as under-express certain proteins, which needs to be considered by scientists using this cell line. Hence, care should be taken to prevent misinterpretation of in vitro obtained findings when translating them to the in vivo situation.

A rare case of enteropathy-type T-cell lymphoma (ETL) developed in a 47-year-old Chinese male 6 years after the diagnosis of diffuse large B-cell lymphoma (DLBCL) in the small intestine. The patient initially presented with vague gastrointestinal complaints. Work-up demonstrated an ulcerated mass in the small intestine. Partial resection and histologic examination of the intestine showed a DLBCL, positive for CD20 and Bcl-2, involving the jejunum transmurally. Further staging work-up demonstrated mesenteric and retroperitoneal lymphadenopathy, splenomegaly, and ascites. The patient was treated aggressively with radiotherapy, chemotherapy, and autologous bone marrow transplant, and complete remission was obtained. Six years later, the patient presented with diarrhea and dehydration. Clinical work-up revealed thickening of the small intestinal wall, and biopsies demonstrated ETL based on morphology, immunohistochemistry, and polymerase chain reaction analysis. Celiac disease was diagnosed concurrently. The patient responded to chemotherapy, received allogeneic peripheral blood stem cell transplantation from an HLA-matched sibling donor, and remains in remission. To our best knowledge, this is the first reported case of metachronous ETL and DLBCL. Possible associations between the 2 types of lymphoma are discussed.

The aims of this study were to examine Li-cadherin expression in 74 gastric carcinoma tissues, 10 cases with normal gastric tissues, and 21 cases with intestinal metaplasia and to investigate the role of Li-cadherin in cell differentiation, cancer invasion, and metastasis. Expression of Li-cadherin was analyzed by immunohistochemistry and semiquantitative polymerase chain reaction and correlated with clinicopathological parameters. Immunohistochemistry showed that Li-cadherin was mainly present on the cell membrane and there was no staining for liver-intestine cadherin in normal tissues. The reduction of Li-cadherin mRNA expression was inversely correlated with the grade of differentiation (P < 0.05). Significant differences in the expression of liver-intestine cadherin were found in lymphatic metastasis of the tumors (P < 0.05), but the expression of liver-intestine cadherin was not associated with gender (P=0.748), serosal invasion (P=0.136), TNM stage (P=0.172), Helicobacter pylori infection (P=0.572), liver metastasis (P=0.374), or peritoneal metastasis (P=0.621). Multivariate analysis revealed that the expression of Li-cadherin is an important predictor of lymph node metastasis. We conclude that there is a significant correlation between Li-cadherin expression and the differentiation of gastric carcinoma, and Li-cadherin can be a good marker to detect gastric cancer at early stages. Increased Li-cadherin expression may contribute to gastric cancer invasion to lymph nodes.

Although the considerable progress against gastric cancer, it remains a complex lethal disease defined by peculiar histological and molecular features. The purpose of the present study was to investigate pRb2/p130, VEGF, EZH2, p53, p16(INK4A), p27(KIP1), p21(WAF1), Ki-67 expressions, and analyze their possible correlations with clinicopathological factors. The expression patterns were examined by immunohistochemistry in 47 patients, 27 evaluated of intestinal-type, and 20 of diffuse-type, with a mean follow up of 56 months and by Western blot in AGS, N87, KATO-III, and YCC-2, -3, -16 gastric cell lines. Overall, stomach cancer showed EZH2 correlated with high levels of p53, Ki-67, and cytoplasmic pRb2/p130 (P < 0.05, and P < 0.01, respectively). Increased expression of EZH2 was found in the intestinal-type and correlated with the risk of distant metastasis (P < 0.05 and P < 0.01, respectively), demonstrating that this protein may have a prognostic value in this type of cancer. Interestingly, a strong inverse correlation was observed between p27(KIP1) expression levels and the risk of advanced disease and metastasis (P < 0.05), and a positive correlation between the expression levels of p21(WAF1) and low-grade (G1) gastric tumors (P < 0.05), confirming the traditionally accepted role for these tumor-suppressor genes in gastric cancer. Finally, a direct correlation was found between the expression levels of nuclear pRb2/p130 and low-grade (G1) gastric tumors that was statistically significant (P < 0.05). Altogether, these data may help shed some additional light on the pathogenetic mechanisms related to the two main gastric cancer histotypes and their invasive potentials.

The receptor tyrosine kinase MET is overexpressed in human colorectal adenomas and carcinomas, suggesting an instrumental role for MET signaling in the onset and progression of colorectal cancer. To corroborate this role, animal models are needed. To study the expression of Met in the normal and neoplastic mouse intestine, we generated an Armenian hamster monoclonal antibody against mouse Met. By using this antibody in immunohistochemical studies, we observed strong Met expression in fetal mouse intestinal epithelial cells. In contrast, in the intestines of adult mice, Met expression was very low whereas the protein was undetectable on the neoplastic epithelium of intestinal adenomas in Apc+/min mice. By immunoblotting, we were also unable to detect Met in intestinal adenomas, whereas Met mRNA levels in microdissected adenomas were very low. The absence of detectable Met protein expression in adenomas of Apc+/min mice contrasts sharply with the vast overexpression of the protein in adenomas of humans with familial adenomatous polyposis or sporadic colorectal carcinomas. Our results imply that deregulation of Wnt signaling in mouse--unlike in human--intestinal epithelium does not result in Met overexpression. Our findings thus reveal important interspecies differences in the regulation of Met expression during intestinal tumorigenesis.

Gastrointestinal adenocarcinoma arising in mature cystic teratomas of the ovary is extremely rare. We report a case of well-differentiated intestinal adenocarcinoma arising in a mature cystic teratoma of the ovary in a 77-year-old woman, presenting as acute abdomen with ovarian torsion. An immunohistochemical study revealed expression of CK20 and CK7, and the tumor was also positive for MUC2. The patient had no evidence of disease after 12 months of follow-up.