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Ten‐eleven translocation 1 (TET1) is an essential methylcytosine dioxygenase of the DNA demethylation pathway. Despite its dysregulation being known to occur in human cancer, the role of TET1 remains poorly understood. In this study, we report that TET1 promotes cell growth in human liver cancer. The transcriptome analysis of 68 clinical liver samples revealed a subgroup of TET1‐upregulated hepatocellular carcinoma (HCC), demonstrating hepatoblast‐like gene expression signatures. We performed comprehensive cytosine methylation and hydroxymethylation (5‐hmC) profiling and found that 5‐hmC was aberrantly deposited preferentially in active enhancers. TET1 knockdown in hepatoma cell lines decreased hmC deposition with cell growth suppression. HMGA2 was highly expressed in a TET1high subgroup of HCC, associated with the hyperhydroxymethylation of its intronic region, marked as histone H3K4–monomethylated, where the H3K27‐acetylated active enhancer chromatin state induced interactions with its promoter. Collectively, our findings point to a novel type of epigenetic dysregulation, methylcytosine dioxygenase TET1, which promotes cell proliferation via the ectopic enhancer of its oncogenic targets, HMGA2, in hepatoblast‐like HCC., Ten‐eleven translocation 1 (TET1), a methylcytosine dioxygenase of the DNA demethylation pathway, is overexpressed in the subgroup of hepatocellular carcinoma with the hepatoblast‐like expression pattern. Comprehensive epigenome profilings revealed the ectopic enhancer activation of HMGA2 through cytosine hydroxymethylation, H3K27 acetylation, H3K4 monomethylation, and promoter‐enhancer interaction in a TET1‐dependent manner.

Cancer develops through the accumulation of genetic and epigenetic aberrations. To identify sequential molecular alterations that occur during the development of hepatocellular carcinoma (HCC), we compared 52 early and 108 overt HCC samples by genome sequencing. Gene mutations in the p53/RB1 pathway, WNT pathway, MLL protein family, SWI/SNF complexes, and AKT/PI3K pathway were common in HCC. In the early phase of all entities, TERT was the most frequently upregulated gene owing to diverse mechanisms. Despite frequent somatic mutations in driver genes, including CTNNB1 and TP53, early HCC was a separate molecular entity from overt HCC, as each had a distinct expression profile. Notably, WNT target genes were not activated in early HCC regardless of CTNNB1 mutation status because β-catenin did not translocate into the nucleus due to the E-cadherin/β-catenin complex at the membrane. Conversely, WNT targets were definitively upregulated in overt HCC, with CTNNB1 mutation associated with downregulation of CDH1 and hypomethylation of CpG islands in target genes. Similarly, cell-cycle genes downstream of the p53/RB pathway were upregulated only in overt HCC, with TP53 or RB1 gene mutations associated with chromosomal deletion of 4q or 16q. HCC was epigenetically distinguished into four subclasses: normal-like methylation, global-hypomethylation (favorable prognosis), stem-like methylation (poor prognosis), and CpG island methylation. These methylation statuses were globally maintained through HCC progression. Collectively, these data show that as HCC progresses, additional molecular events exclusive of driver gene mutations cooperatively contribute to transcriptional activation of downstream targets according to methylation status. Significance: In addition to driver gene mutations in the WNT and p53 pathways, further molecular events are required for aberrant transcriptional activation of these pathways as HCC progresses.

Entosis is a type of regulated cell death that promotes cancer cell competition. Though several studies have revealed the molecular mechanisms that govern entosis, the clinical and genetic correlates of entosis in human tumors is less well understood. Here we reviewed entotic cell-in-cell (CIC) patterns in a large single institution sequencing cohort (MSK IMPACT clinical sequencing cohort) of more than 1600 human pancreatic ductal adenocarcinoma (PDAC) samples to identify the genetic and clinical correlates of this cellular feature. After case selection, 516 conventional PDACs and 21 ASCs entered this study and ~45,000 HPFs (median 80 HPFs per sample) were reviewed; 549 entotic-CICs were detected through our cohort. We observed that entotic-CIC occurred more frequently in liver metastasis compared with primary in PDAC. Moreover, poorly differentiated adenocarcinoma or adenosquamous carcinoma had more entotic-CIC than well or moderately differentiated adenocarcinoma. With respect to genetic features TP53 mutations, KRAS amplification, and MYC amplification were significantly associated with entosis in PDAC tissues. From a clinical standpoint entotic CICs were independently associated with a poor prognosis by multivariate Cox regression analysis when considering all cases or primary PDACs specifically. These results provide a contextual basis for understanding entosis in PDAC, a highly aggressive cancer for which molecular insights are needed to improve survival.

Surgery is the only curative option for stage I/II pancreatic cancer; nonetheless, most patients will experience a recurrence after surgery and die of their disease. To identify novel opportunities for management of recurrent pancreatic cancer, we performed whole-exome or targeted sequencing of 10 resected primary cancers and matched intrapancreatic recurrences or distant metastases. We identified that recurrent disease after adjuvant or first-line platinum therapy corresponds to an increased mutational burden. Recurrent disease is enriched for genetic alterations predicted to activate MAPK/ERK and PI3K–AKT signaling and develops from a monophyletic or polyphyletic origin. Treatment-induced genetic bottlenecks lead to a modified genetic landscape and subclonal heterogeneity for driver gene alterations in part due to intermetastatic seeding. In 1 patient what was believed to be recurrent disease was an independent (second) primary tumor. These findings suggest routine post-treatment sampling may have value in the management of recurrent pancreatic cancer. Significance: The biological features or clinical vulnerabilities of recurrent pancreatic cancer after pancreaticoduodenectomy are unknown. Using whole-exome sequencing we find that recurrent disease has a distinct genomic landscape, intermetastatic genetic heterogeneity, diverse clonal origins, and higher mutational burden than found for treatment-naïve disease. See related commentary by Bednar and Pasca di Magliano, p. 762. This article is highlighted in the In This Issue feature, p. 747

Crucial transitions in cancer-including tumor initiation, local expansion, metastasis, and therapeutic resistance-involve complex interactions between cells within the dynamic tumor ecosystem. Transformative single-cell genomics technologies and spatial multiplex in situ methods now provide an opportunity to interrogate this complexity at unprecedented resolution. The Human Tumor Atlas Network (HTAN), part of the National Cancer Institute (NCI) Cancer Moonshot Initiative, will establish a clinical, experimental, computational, and organizational framework to generate informative and accessible three-dimensional atlases of cancer transitions for a diverse set of tumor types. This effort complements both ongoing efforts to map healthy organs and previous large-scale cancer genomics approaches focused on bulk sequencing at a single point in time. Generating single-cell, multiparametric, longitudinal atlases and integrating them with clinical outcomes should help identify novel predictive biomarkers and features as well as therapeutically relevant cell types, cell states, and cellular interactions across transitions. The resulting tumor atlases should have a profound impact on our understanding of cancer biology and have the potential to improve cancer detection, prevention, and therapeutic discovery for better precision-medicine treatments of cancer patients and those at risk for cancer.

Background:The clinical course of hepatocellular carcinoma (HCC) is complicated, because it often recurs and shows multiple lesions, some of which progress to a more malignant form, shortening the life of the patient. The hepatocyte growth factor receptor c-Met has been shown to play an important role in the pathogenesis of HCC, but the influence of c-Met expression on the clinical course of HCC remains to be fully elucidated. Methods:We randomly selected and included 600 tumor specimens obtained from the primary and recurrent lesions of 319 HCC cases between 1995 and 2007. The expression of c-Met was determined by immunohistochemistry using archived formalin-fixed paraffin-embedded samples. We analyzed the correlation between c-Met expression and clinical parameters, including survival. In addition, we examined c-Met expression in the malignant transition of HCC in all cases including recurrent lesions. Results:Survival analysis using the multivariate Cox proportional-regression model revealed that the prognosis was significantly better in the primary cases with high c-Met expression than in those with low c-Met expression (hazard ratio 0.159, 95% confidence interval 0.065–0.391; p < 0.001). During the course of recurrence, some cases with high c-Met expression returned to low c-Met expression. Among 40 cases with high c-Met expression, 29 survived more than 2 years after detecting the high c-Met expression. Conclusion:High expression of c-Met may be a prognostic factor for a good, rather than a poor, HCC prognosis. The involvement of c-Met expression in the malignant transition of recurrent HCC is obscure.

We present two cases of diffusely decreased liver attenuation on post-mortem computed tomography (CT) which is lower than that on ante-mortem CT. Cases include a 37-year-old female whose cause of death was related to myelodysplastic syndrome (Case #1) and an 88-year-old female whose cause of death was related to malignant lymphoma (Case #2). We compared post-mortem CT (PMCT) liver attenuations with those on ante-mortem CT (AMCT). For Case #1, average AMCT values of the right/left liver were 46.1/50.0 Hounsfield Units (HU) 2 days ante-mortem and PMCT values of the right/left liver were 33.9/38.4 HU 3 h post-mortem. For Case #2, average AMCT values were 61.4/54.9 HU 5 days ante-mortem and PMCT values of the right/left liver were 38.2/40.6 HU 2 h post-mortem. In both Case # 1 and #2, decreased liver attenuations were found on PMCT. Further, autopsy revealed diffuse hepatocellular hemorrhage, deficits, and necrosis in Case #1, and liver infiltration of lymphoma in Case #2. These pathological findings were considered to be related to diffusely decreased liver attenuation on PMCT in conjunction with remarkable deterioration of hepatobiliary function before death. The observed decreases in liver attenuation on PMCT may be attributed mainly to hepatic pathological changes just prior to death. PMCT liver attenuation does not necessarily reflect the ante-mortem state some time before death, and it is therefore necessary to be careful when presuming the ante-mortem hepatic pathological conditions from only PMCT. This attenuation change should be taken into account during PMCT interpretation.

Adenosquamous cancer of the pancreas (ASCP) is a subtype of pancreatic cancer that has a worse prognosis and greater metastatic potential than the more common pancreatic ductal adenocarcinoma (PDAC) subtype. To distinguish the genomic landscape of ASCP and identify actionable targets for this lethal cancer, we applied DNA content flow cytometry to a series of 15 tumor samples including five patient-derived xenografts (PDX). We interrogated purified sorted tumor fractions from these samples with whole-genome copy-number variant (CNV), whole-exome sequencing, and Assay for Transposase-Accessible Chromatin using sequencing (ATAC-seq) analyses. These identified a variety of somatic genomic lesions targeting chromatin regulators in ASCP genomes that were superimposed on well-characterized genomic lesions including mutations in TP53 (87%) and KRAS (73%), amplification of MYC (47%), and homozygous deletion of CDKN2A (40%) that are common in PDACs. Furthermore, a comparison of ATAC-seq profiles of three ASCP and three PDAC genomes using flow-sorted PDX models identified genes with accessible chromatin unique to the ASCP genomes, including the lysine methyltransferase SMYD2 and the pancreatic cancer stem cell regulator RORC in all three ASCPs, and a FGFR1-ERLIN2 fusion associated with focal CNVs in both genes in a single ASCP. Finally, we demonstrate significant activity of a pan FGFR inhibitor against organoids derived from the FGFR1-ERLIN2 fusion–positive ASCP PDX model. Our results suggest that the genomic and epigenomic landscape of ASCP provide new strategies for targeting this aggressive subtype of pancreatic cancer. Significance: These data provide a unique description of the ASCP genomic and epigenomic landscape and identify candidate therapeutic targets for this dismal cancer.

Trimethylation of histone H3 at lysine 27 (H3K27me3) acts as a transcriptional repressor of target genes. Recent immunohistochemical studies have reported a loss of H3K27me3 modification in diffuse (especially 1p/19q-codeleted) gliomas. However, we did not observe H3K27me3 loss in diffuse gliomas using routine immunostaining conditions for the detection of H3K27me3 loss in malignant peripheral nerve sheath tumors (MPNSTs). Therefore, we conducted immunohistochemical analysis of surgically resected specimens to understand the differences in the H3K27me3 status in MPNSTs and diffuse gliomas and evaluate the diagnostic utility of H3K27me3 immunohistochemistry. Staining with a standard 1:200 dilution of the C36B11 antibody showed a complete loss of H3K27me3 in 5 out of 11 MPNSTs, whereas most diffuse gliomas (149/151, 98.7%) showed diffuse immunoreactivity. At a 1:2000 antibody dilution, 12.6% (19/151) of the diffuse gliomas showed H3K27me3 loss, which was significantly associated with 1p/19q codeletion (P

Purpose: Melanoma is a biologically heterogeneous disease composed of distinct clinicopathologic subtypes that frequently resist treatment. To explore the evolution of treatment resistance and metastasis, we used a combination of temporal and multilesional tumor sampling in conjunction with whole-exome sequencing of 110 tumors collected from 7 patients with cutaneous (n = 3), uveal (n = 2), and acral (n = 2) melanoma subtypes. Experimental Design: Primary tumors, metastases collected longitudinally, and autopsy tissues were interrogated. All but 1 patient died because of melanoma progression. Results: For each patient, we generated phylogenies and quantified the extent of genetic diversity among tumors, specifically among putative somatic alterations affecting therapeutic resistance. Conclusions: In 4 patients who received immunotherapy, we found 1–3 putative acquired and intrinsic resistance mechanisms coexisting in the same patient, including mechanisms that were shared by all tumors within each patient, suggesting that future therapies directed at overcoming intrinsic resistance mechanisms may be broadly effective.

Pancreatic cancer expression profiles largely reflect a classical or basal-like phenotype. The extent to which these profiles vary within a patient is unknown. We integrated evolutionary analysis and expression profiling in multiregion-sampled metastatic pancreatic cancers, finding that squamous features are the histologic correlate of an RNA-seq-defined basal-like subtype. In patients with coexisting basal and squamous and classical and glandular morphology, phylogenetic studies revealed that squamous morphology represented a subclonal population in an otherwise classical and glandular tumor. Cancers with squamous features were significantly more likely to have clonal mutations in chromatin modifiers, intercellular heterogeneity for MYC amplification and entosis. These data provide a unifying paradigm for integrating basal-type expression profiles, squamous histology and somatic mutations in chromatin modifier genes in the context of clonal evolution of pancreatic cancer. Iacobuzio-Donahue and colleagues use integrated transcriptomic, histologic and mutational data to analyze squamous features of pancreatic ductal adenocarcinoma (PDAC), further refining the understanding of heterogeneity and evolution in PDAC.

Summary In the female genital tract, extrauterine leiomyomas such as those that arise in the ovary and paraovarian/paratubal regions are rare. Currently, little is known about the background genetic changes in such adnexal leiomyomas. Recent studies have found that the MED12 mutation is common in uterine leiomyomas, which suggests that such mutations may play an oncogenic role in smooth muscle neoplasms in females. Herein, we examined a series of ovarian and other adnexal leiomyomas in terms of MED12 mutational status to investigate possible MED12 involvement in the pathogenesis of extrauterine smooth muscle tumors. We evaluated 10 cases of adnexal leiomyomas (5 ovarian, 3 paraovarian, and 2 paratubal) and 49 cases of ovarian sex cord–stromal tumors as controls. We performed polymerase chain reaction followed by direct sequencing of exon 2 of MED12, and immunohistochemical staining for smooth muscle actin and desmin. We identified somatic MED12 mutations in 90% (9/10) of the adnexal leiomyomas. None of the sex cord–stromal tumors in the control group harbored MED12 mutations. Diffuse immunoreactivity for both smooth muscle actin and desmin was characteristic of adnexal leiomyomas only. Thus, we conclude that ovarian leiomyomas are distinct from sex cord–stromal tumors. MED12 mutations are key molecular features of ovarian and other adnexal leiomyomas. We speculate that the pathogenesis of adnexal leiomyoma is similar to that of its uterine counterpart.

CLDN18-ARHGAP26/6 fusions have been identified in gastric cancers, with a predominance in diffuse-type gastric cancers (DGCs). Although in vitro experiments have suggested an oncogenic role for CLDN18-ARHGAP26/6 fusions, the exact frequencies and clinicopathological characteristics of the fusion-positive cases are poorly understood. We analyzed 254 cases of gastric cancer (172 diffuse-type and 82 intestinal-type) using RT-PCR and FISH, and also analyzed TCGA transcriptome datasets to identify genes that are related to the aggressive behaviors of fusion-positive cancers. Our assays identified 26 fusion-positive cases, 22 of which were DGCs (22/172, 12.8%). Unlike fusion-negative DGCs, almost all fusion-positive DGCs retained E-cadherin expression (P = 0.036). Fusion-positive DGCs also showed a higher prevalence of lymphatic and distant organ metastases, and these trends were only significant in the younger age group (< 60 years). In this group, the majority of cases with distant organ metastases (4 of 6 cases) were fusion-positive, and the multivariate regression analysis revealed that fusion status was an independent predictive marker for distant organ metastases (P = 0.002). In the TCGA dataset analysis, carbonic anhydrase 9 was postulated to be a potential modulator of the age-specific effects of the fusion protein, compatible with the immunohistochemical analysis of our cohort. Therefore, CLDN18-ARHGAP26/6 fusion-positive DGCs are considered biologically distinct entities that will require more advanced therapeutic options.

A 68-year-old male who had undergone low anterior resection for primary rectal cancer 19 months ago presented with multiple CLM at Couinaud's segments IV, V, and VIII. There was no apparent macroscopic intrabiliary growth on preoperative computed tomography and gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid-enhanced magnetic resonance imaging (EOB-MRI). However, the hepatobiliary phase of EOB-MRI revealed peritumoral low signal intensity in lesions in segments V and VIII, which indicates vascular invasion around hepatocellular carcinoma. Contrast-enhanced intraoperative ultrasound (CE-IOUS) clearly determined the extent of macroscopic glissonean growth from lesions in segments V and VIII, and more extensive resection was performed than was planned. Analysis of the resected specimens from segments V and VIII confirmed the presence of macroscopic intrabiliary growth with microscopic portal vein invasion. All three CLM were histopathologically diagnosed as well-to-moderately differentiated adenocarcinoma, and R0 resection was verified. Postoperative recovery was uneventful, and the patient was alive without evidence of recurrence 12 months after hepatic resection. CE-IOUS should be considered at the time of CLM resection, as it might enable more accurate detection of macroscopic intrabiliary growth of CLM, and enable resection with safer margins.

Background Only a few studies have reported the resection and reconstruction of major hepatic veins during hepatectomy. Here we present our strategy and techniques for venous reconstruction with cryopreserved homologous veins, and describe the surgical outcome. Methods Among 2387 hepatectomy patients, 39 patients who required hepatic venous reconstruction were reviewed retrospectively. Venous reconstruction was performed to secure a non-congested liver remnant volume of at least 40% of the total liver volume. Results There was no operative mortality, and the severe morbidity rate was 5% in this series. A total of 41 veins were reconstructed; 30 with homologous veins (73.2%) and 11 with autologous veins (26.8%), with the middle hepatic vein being the most frequent (n=23, 56%). Interposition grafting was performed more often (P=0.003), the length of the venous resection was longer (P=0.007), and pathologic wall infiltration of the vein was revealed more often (P=0.002) in the homologous graft group than in the autologous graft group. The 1-, 2-, and 3-year overall patency of the reconstructed veins was 55.4%, 46.3%, and 46.3%, respectively. Conclusions Aggressive venous reconstruction during hepatectomy using cryopreserved homologous veins is a feasible option with satisfactory short-term outcomes, and may be warranted to improve operative safety. This article is protected by copyright. All rights reserved.

Temsirolimus is an inhibitor of mammalian target of rapamycin and interstitial lung disease (ILD) is known to be one of the adverse events associated with temsirolimus, which usually improves rapidly after discontinuation of the drug and rarely worsens thereafter. Herein, we report a case of delayed exacerbation of ILD after discontinuation of temsirolimus for metastatic renal cell carcinoma in an 86-year-old male with chronic ILD. The patient developed gradually worsening dyspnea five weeks after an initiation of temsirolimus and was admitted to our facility. On his admission, although a pulmonary function test revealed a decreased diffusion capacity, there was no obvious progression of ILD on HRCT scan. His dyspnea once improved after discontinuation of temsirolimus, but it recurred and acute exacerbation of ILD was diagnosed 40 days after his last administration of temsirolimus. He received high-dose steroid therapy, however, he deteriorated and died. Histopathological examination of the lungs at autopsy revealed overlapping diffuse alveolar damage with chronic interstitial changes. In the present case, since there were no specific factors that could have caused acute exacerbation of ILD except for temsirolimus, it was considered to contribute to the exacerbation of underlying ILD. In conclusion, physicians should be aware of the possibility of temsirolimus-induced ILD not only while the medication is administered, but also even after it is discontinued. It is important to carefully interview the patient and to recognize the value of physiological tests, such as respiratory function tests and blood gas analysis, as well as imaging findings on HRCT.

Gastrointestinal stromal tumors (GISTs) of the vermiform appendix are rare, measuring

Colorectal cancer resembling submucosal tumor (SMT) is very rare. We herein report two cases of small colon carcinoma resembling SMT (80-year-old female and 67-year-old male), which massively invaded into the submucosal layer and accompanied marked lymphatic invasion and lymph node metastasis. We also reviewed the reported cases of colorectal carcinoma resembling SMT (SMT-like group, n=70) and analyzed the clinicopathological characteristics of this group compared with typical colorectal carcinoma cases operated at our institution (control group, n=1723). Tumors in the SMT-like group were significantly smaller in size compared with the control group; the median diameter measured 22mm vs. 37mm (P0.01), respectively. Histologically, although the tumors in the SMT-like group were small in diameter, they almost all invaded into the submucosal (T1) or deeper layer (T2-4), and the rate of poorly differentiated adenocarcinoma or mucinous adenocarcinoma was significantly higher than that in the control group (48.6% vs. 7.7%; P0.01). In the subgroup analysis of T1 tumors, the rate of lymphatic invasion in the SMT-like group was also significantly higher than that in the control group (43.8% vs. 15.4%; P0.01). Carcinoma resembling SMT appears to be invasive and has a high risk of lymphatic invasion even if small in size. Therefore, surgical treatment with dissection of the regional lymph nodes might be necessary in cases with any signs of massive submucosal invasion.

Aims BAP1 and PBRM1 expression loss has been observed in multiple cancers, including intrahepatic cholangiocarcinoma (ICC). We investigated BAP1 and PBRM1 expression in ICC using immunohistochemistry, and analyzed its association with clinicopathological and genetic features, including two histologic subtypes. Methods and results Whole-section slides of 108 consecutive primary ICC cases were immunostained against BAP1 and PBRM1. Complete loss of BAP1 and PBRM1 was observed in 21 (19.4%) and 25 (23.1%) cases, respectively, and partial loss was identified in 4 (3.7%) and 9 (8.4%) cases. In all cases, normal bile ducts were strongly and diffusely positive for both BAP1 and PBRM1. ICC with BAP1 loss showed lower serum CA19-9 levels, less perineural invasion, rare mucin production, weaker immunoreactivity against S-100P, and stronger immunoreactivity against N-cadherin and NCAM. IDH mutations were identified more frequently in ICCs with BAP1 loss. All ICC with BAP1 loss corresponded to small-duct-type ICC. Multivariate Cox regression analysis showed that BAP1 loss was an independent prognostic factor for both overall and recurrence-free survival (P < 0.05). PBRM1 loss, on the other hand, was found in both small-duct-type and large-duct-type ICC, and was not significantly associated with any specific characteristics, including prognosis. Conclusion BAP1 and PBRM1 loss is frequently seen in ICC. ICC with BAP1 loss shares features of small-duct-type ICC. This article is protected by copyright. All rights reserved.

Surgery is the only curative option for Stage I/II pancreatic cancer, nonetheless most patients will recur after surgery and die of their disease. To identify novel opportunities for management of recurrent pancreatic cancer we performed whole exome or targeted sequencing of 10 resected primary cancers and matched intrapancreatic recurrences or distant metastases. We identified that adjuvant or first-line platinum therapy corresponds to an increased mutational burden of recurrent disease. Recurrent disease is enriched for mutations that activate Mapk/Erk and PI3K/AKT signaling and develops from a monophyletic or polyphyletic origin. Treatment induced genetic bottlenecks lead to a modified genetic landscape and subclonal heterogeneity for driver gene alterations in part due to intermetastatic seeding. In one patient what was believed to be recurrent disease was an independent (second) primary tumor. These findings advocate for combination therapies with immunotherapy and routine post-treatment sampling as a component of management of recurrent pancreatic cancer.

Intrahepatic cholangiocarcinoma (ICC) is an extremely aggressive carcinoma. Useful predictors for the patients' prognosis after surgery have not been fully established. From the University of Tokyo Hospital pathology archives, we reviewed 107 cases of ICC, 54 cases of perihilar cholangiocarcinoma, and 40 cases of extrahepatic cholangiocarcinoma (ECC); we also investigated the significance of tumor budding in ICC, in comparison with perihilar cholangiocarcinoma and ECC. The tumor-budding frequencies were different by tumor location: 40.2% (43/107) in ICC, 70.4% (38/54) in perihilar cholangiocarcinoma, and 60.0% (24/40) in ECC. Tumor budding in ICC was associated with many pathologic indicators associated with invasion, such as major vascular invasion (P=0.012) and Union for International Cancer Control stage (P=0.007). Univariate and multivariate Cox regression analyses revealed tumor budding as a powerful prognostic factor for both recurrence-free survival (RFS) and overall survival (OS) in ICC by univariate (RFS: hazard ratio [HR]: 2.666; 95% confidence interval [CI]: 1.517-4.683, OS: HR: 4.206; 95% CI: 2.447-7.230) and by multivariate analyses (RFS: HR: 3.038; 95% CI: 1.591-5.973, OS: HR: 4.547, 95% CI: 2.348-8.805). Tumor budding was also a significant prognostic factor of perihilar cholangiocarcinoma, but not of ECC. When ICC was divided into 2 subtypes, type 1 (hilar) and type 2 (peripheral), tumor budding was the strong prognostic factor in type 2 ICC, but not in type 1 ICC, suggesting that some differences in biological behavior exist between type 1 ICC and perihilar cholangiocarcinoma. Tumor budding is prognostically important in ICC, and its pathogenetic role in biliary tract carcinomas might be different by anatomic location.

Highlights • A hepatic schwannoma is extremely rare and difficult to diagnose preoperatively. • We attempted to gain the radiological feature of the hepatic schwannoma by reviewing case reports. • If the hepatic tumor is diagnosed as a schwannoma preoperatively, surgical resection is highly recommended., Introduction A hepatic schwannoma is extremely rare and difficult to diagnose preoperatively. Presentation of case We report the case of a 47-year-old male patient who was referred to our hospital for the close investigation of a hepatic tumor which had not been detected two years earlier. An enhanced computed tomography revealed a well-circumscribed and encapsulated tumor with a size of 50 mm which was adjacent to the inferior vena cava (IVC) and the right hepatic vein. The tumor was heterogeneously enhanced until the equilibrium phase. A magnetic resonance image showed a hypointense area on a T1-weighted image and a hyperintense area on a T2-weighted image. These findings differed from those of common malignant hepatic tumors, such as hepatocellular carcinoma and colorectal liver metastases. The tumor was most likely a mucus-producing tumor or a liquefactive degenerated adenocarcinoma. Although we could not confirm an exact diagnosis of the tumor, we performed a surgical resection in view of the possibility of malignancy. The patient underwent a limited liver resection with resection of the IVC. Histologically, the tumor was diagnosed as a benign schwannoma comprised of Antoni A and B areas. The nuclear palisading formation of the tumor showed Verocay bodies. Discussion 15 cases of hepatic schwannoma are reviewed to clarify the typical radiological features. The radiological findings of the present case were consistent with those of the hepatic schwannoma when considering retrospectively. Conclusion A precise preoperative diagnosis of hepatic schwannoma is difficult, and liver resection is recommended when a hepatic schwannoma is suspected.

Aims Hidradenoma papilliferum (HP) is a benign vulvar neoplasm that arises from anogenital mammary-like glands, and its morphology is similar to mammary intraductal papilloma. The aim of this study was to investigate oncogenic mutations involved in the tumourigenesis of HP. We focused specifically on PIK3CA and AKT1 mutations, which are both reported to be detected in 33% of mammary intraductal papillomas. Methods In total, seven HP cases were analysed. Clinicopathological analyses and immunohistochemistry for oestrogen receptor, p63, smooth muscle actin (SMA), p53 and β-catenin were performed. Furthermore, PIK3CA , AKT1, BRAF and KRAS hot spot mutations were examined by Sanger sequencing. Results Morphologically, all HPs had a papillary and tubular architecture with a biphasic pattern of epithelial and myoepithelial cells. Immunohistochemistry revealed that oestrogen receptor expression was restricted to epithelial cells, whereas p63 and SMA were exclusively expressed in myoepithelial cells. The patterns of p53 and β-catenin immunostaining suggested wild-type genotypes. Direct sequencing revealed the presence of somatic PIK3CA mutations (Ex9. c.1633G>A, p.E545K and Ex20. c.3140A>G, p.H1047R) in two of the HPs and an AKT1 (c.49G>A, p.E17K) mutation in one. BRAF and KRAS mutations were not found in any of the HP cases. Conclusions PIK3CA and AKT1 are frequently mutated in HP tumours (29% and 14%, respectively). PIK3CA/AKT1 pathway alterations in HP further support the hypothesis that HP is the vulvar (anogenital mammary-like gland) analogue of breast intraductal papilloma.

Immunohistochemical analysis using specific antibodies is a useful and convenient method to detect proteins altered by somatic mutations. We previously generated the rat monoclonal antibody MsMab-2, which recognizes isocitrate dehydrogenase (IDH)1 R132L and IDH2 R172M. In the present study, we used an immunohistochemical method to examine MsMab-2 immunoreactivity in 95 cases of intrahepatic cholangiocarcinoma, including five IDH1 R132L and one IDH2 R172M mutant cases confirmed by direct sequencing. Tissue microarray section slides of all IDH1/2-mutant and wild-type cases, as well as whole section slides of IDH1 R132L and IDH2 R172M cases were immunostained using an autostainer. All IDH1 R132L cases showed positive staining for MsMab-2, while other IDH1/2 mutant and IDH1/2 wild-type cases were negative. Tumor cells of the immunopositive cases invariably showed strong reactivity using whole-section slides. We consider immunohistochemical analysis using MsMab-2 to be a useful means of detecting IDH1 R132L. Further analysis of its effectiveness against IDH2 R172M is necessary because of the small sample size in this study.

Previous studies have identified 2 clinically significant morphologic subtypes of intrahepatic cholangiocarcinoma (ICC) on the basis of anatomic location and/or histologic appearances. Recognizing that these classification schemes are not always applicable practically, this study aimed to establish a novel classification system based on mucin productivity and immunophenotype and to determine the rationale of this classification by examining the clinicopathologic and genetic characteristics of the 2 subtypes defined by this method. We retrospectively investigated 102 consecutive ICC cases and classified them on the basis of mucin productivity and immunophenotype (S100P, N-cadherin, and NCAM). We found that 42 and 56 cases were classified as type 1 and type 2 ICCs, respectively, and only 4 cases were of indeterminate type. Type 1 ICC, generally characterized by mucin production and diffuse immunoreactivity to S100P, arose less frequently in chronic liver diseases and showed higher levels of serum CEA and CA 19-9 than did type 2 ICC, which generally showed little mucin production and exhibited immunoreactivity to N-cadherin and/or NCAM. Type 1 ICC was characterized by several pathologic features, including higher frequencies of perineural invasion and lymph node metastasis. Although the log-rank test demonstrated that type 1 ICC had significantly worse survival, the multivariate Cox regression analysis showed no prognostic significance of this histologic subtype. Genetic analyses revealed that KRAS mutation was significantly more frequent in type 1 ICC, whereas IDH mutation and FGFR2 translocation were restricted to type 2 ICC. In conclusion, the present classification of ICC based on mucin productivity and immunophenotype identified 2 subtypes with clinicopathologic significance.

The development of nephrotic syndrome (NS) after umbilical cord transplantation (UBT) has been reported in only four cases to date. We herein report the case of a 50-year-old woman who developed NS 94 days after UBT. She fell into oliguria and required dialysis. A kidney biopsy revealed focal and segmental glomerulosclerosis. Although glucocorticoid monotherapy did not improve her condition, the addition of low-density lipoprotein (LDL) apheresis resulted in remission of NS, a drastic improvement in her renal function, and withdrawal from dialysis. To the best of our knowledge, this is the first report of UBT-associated NS treated with LDL apheresis.

Ecotropic virus integration site 1 protein homolog (EVI1), a well-known oncogenic transcriptional factor of hematopoietic cells, contributes to pancreatic cancer oncogenicity through increased expression of KRAS. Because EVI1 was upregulated in cholangiocarcinoma by referring The Cancer Genome Atlas, we investigated the importance of EVI1 in intrahepatic cholangiocarcinoma (ICC) which has been regarded as a heterogeneous group of cancers. Immunohistochemical analysis results demonstrated that EVI1 was overexpressed in about half of ICC (53/101, 52.5%). Moreover, all intraductal papillary neoplasms of the bile duct cases expressed EVI1 regardless of histological grading and subtypes such as gastric, intestinal, pancreatobiliary, or oncocytic (20/20, 100%). EVI1-positive ICC showed higher frequencies of aggressive pathological indicators such as periductal infiltrative growth (p = 0.022), hilar invasion (p = 0.041), advanced UICC stage (p = 0.026), major vascular invasion (p = 0.026), and perineural invasion (p = 0.007) than EVI1-negative ICC. Patients with EVI1-positive ICC showed worse overall survival and recurrence-free survival in all resected cases and in curative resected cases. Recently, we proposed type 1/2 (large/small duct types) classification of ICC based on mucin productivity and immunophenotypes (S100P, N-cadherin, and NCAM). Type 1 predominantly consisted of EVI1-positive ICC (33/42 cases, 79%), and the frequency was significantly higher than type 2 (18/55 cases, 32.7%) (p

In the present study, we investigated the clinicopathologic significance of intratumoral lymphoplasmacytic infiltration in a large cohort of patients with solitary hepatocellular carcinoma (HCC). Based on examination of hematoxylin and eosin-stained sections, significant infiltration was defined as dense lymphoplasmacytic infiltration, either multifocal or diffuse, in 2 or more fields under low-power magnification. Of 544 cases, 216 (39.7%) were positive for significant infiltration (HCC-LI group), while 328 (60.3%) were negative (HCC-NLI group). There were no significant between-group differences in patient age, sex, or background etiology. The lower incidence of Child-Pugh stage B (P = 0.001) and lower level of indocyanine green retention rate at 15 minutes (P < 0.001) in the HCC-LI group indicated better liver function in this group. Histologically, tumors were significantly smaller in size in the HCC-LI group than in the HCC-NLI group (P < 0.001). In addition, prominent neutrophilic infiltration, interstitial fibrosis and tumor steatosis were significantly more frequent (P < 0.001) in the HCC-LI group, while tumor necrosis was significantly less frequent (P = 0.008). Kaplan-Meier analyses revealed that overall and recurrence-free survival were significantly better in the HCC-LI group (P < 0.001). Multivariate Cox regression analysis showed that intratumoral lymphoplasmacytic infiltration was independently prognostic of both overall and recurrence-free survival (P < 0.001), with absence of infiltration showing high Cox-hazard ratios for poor prognosis. In conclusion, intratumoral lymphoplasmacytic infiltration, as determined by assessment of hematoxylin and eosin-stained slides, was significantly associated with the clinical and pathologic features of HCC and has profound prognostic importance.

Background Non-occlusive mesenteric ischemia (NOMI) is ischemia of the mesentery that is caused by hypoperfusion or vasospasm without any thrombosis. NOMI is difficult to diagnose by physical examination alone. Although angiographic examination of the superior mesenteric artery (SMA) is the usual diagnostic method used, it is an invasive examination. Usually, a long range of the bowel becomes discontinuously necrotic in NOMI. Here, we report a rare case of NOMI localized in the transverse colon that was diagnosed by computed tomography (CT) angiography which is a minimally invasive examination. Case presentation A 72-year-old woman was referred to our hospital for further treatment of abdominal pain that developed 1 day before presentation. Contrast-enhanced abdominal CT scan revealed attenuated enhancement of the transverse colon. CT angiography showed SMA irregularities due to vasospasm. The middle colic artery could not be detected by CT angiography. No occlusion due to thrombus or embolism in the SMA and superior mesenteric vein was observed. Based on the findings, NOMI was suspected, and emergency laparotomy was performed, which revealed a segmentally necrotic transverse colon. The necrotic bowel was resected, and stomas were created. Conclusion The presence of hypotension in the patient necessitated the use of CT angiography, which proved very useful in the early diagnosis of the present case. Thus, if intestinal ischemia is suspected, even in case of a short segment, CT angiography should be performed.