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Purpose: Intraoperative control of air leaks is important for preventing prolonged air leaks after surgery. The usefulness of suturing free pericardial fat pads (FPFPs) as pledgets for repairing air leaks was investigated., Methods: A total of 111 patients who underwent anatomical lung resection and required suture repair for intraoperative air leaks were retrospectively reviewed. Mattress sutures were performed using polyglycolic acid (PGA) sheets (PGA group; n = 60) in the early period (April 2014 to March 2018) and FPFPs (FPFP group; n = 51) in the late period (April 2018 to March 2021) as pledgets., Results: More patients had a history of smoking in the FPFP group than in the PGA group. The duration of air leakage was significantly shorter (mean 1.2 vs. 3.5 days, p = 0.002) and prolonged air leakage (> 5 days) was less frequently observed (23.3% vs. 5.9%, p = 0.016) in the FPFP group than in the PGA group. The FPFP group had fewer cases requiring pleurodesis and with recurrent air leaks than in the PGA group. In one case in the FPFP group, fat necrosis with fibrosis and fibrous adhesion to the visceral pleura was found on a pathological examination., Conclusion: Parenchymal repair using FPFPs as pledgets can reduce prolonged air leaks after surgery., (© 2022. The Author(s) under exclusive licence to Springer Nature Singapore Pte Ltd.)

Objectives: To evaluate the diagnostic performance of quantitative values and MRI findings for differentiating seromucinous borderline tumours (SMBTs) from endometriosis-related malignant ovarian tumours (MT)., Methods: This retrospective study examined 19 lesions from SMBT and 84 lesions from MT. The following quantitative values were evaluated using receiver-operating characteristic analysis: overall and solid portion sizes, fluid signal intensity (SI), degree of contrast-enhancement, and mean and minimum apparent diffusion coefficient (ADC) values of the solid portion. Two radiologists independently evaluated four MRI findings characteristic of SMBT, fluid SI on the T1-weighted image and SI of the solid portion on diffusion-weighted image. The diagnostic values of these findings and interobserver agreement were assessed., Results: For diagnosing SMBT, the mean ADC value of the solid portion showed the greatest area under the curve (0.860) (cut-off value: 1.31 × 10 -3 mm 2 /s, sensitivity: 1.00, specificity: 0.61). The T2-weighted image (T2WI) high SI solid portion was the most useful finding, with high specificity and interobserver agreement (sensitivity, 0.58; specificity, 0.95-0.96, kappa = 0.96), followed by T2WI low SI core (sensitivity, 0.48-0.63; specificity, 0.98, kappa = 0.68)., Conclusion: Mean ADC values of the solid portion, T2WI high SI solid portion, and T2WI low SI core were useful for differentiating SMBT from MT., Key Points: • SMBT is a newly categorised ovarian tumour often associated with endometriosis. • Differentiation of SMBT from endometriosis-related malignant ovarian tumour is clinically important. • Diagnostic performances of quantitative values and MRI findings were evaluated. • Mean ADC value of the solid portion was the most useful value. • "T2WI high SI solid portion" was the most useful MRI finding.

Objective: A precise preoperative diagnosis of in situ or minimally invasive carcinoma may identify patients who can be treated by limited resection. Although some clinical trials of limited resection for lung cancer have started, it will take a long time before the results will be published. We have already reported a large-scale study of limited resection. We herein report the data for a subclass analysis according to differences in pathology., Methods: Data from multiple institutions were collected on 1710 patients who had undergone limited resection (segmentectomy or wedge resection) for cT1N0M0 non-small cell carcinoma. The disease-free survival (DFS) and recurrence-free proportion (RFP) were analyzed. Small cell carcinomas and carcinoid tumors were excluded from this analysis. Adenocarcinomas were sub-classified into four groups using two factors, the ratio of consolidation to the tumor diameter (C/T) and the tumor diameter alone., Results: The median patient age was 64 (20-75) years old. The mean maximal diameter of the tumors was 1.5 ± 0.5 cm. The DFS and RFP at 5 years based on the pathology were 92.2 and 94.7 % in adenocarcinoma (n = 1575), 76.3 and 82.4 % in squamous cell carcinoma (SqCC) (n = 100), and 73.6 and 75.9 % in patients with other tumors (n = 35). The prognosis of adenocarcinoma in both groups A (C/T ≤0.25 and tumor diameter ≤2.0 cm) and B (C/T ≤0.25 and tumor diameter >2.0 cm) was good. In SqCC, only segmentectomy was a favorable prognostic factor. In the groups with other pathologies, large cell carcinomas were worse in prognosis (the both DFS and RFP: 46.3 %)., Conclusion: Knowing the pathological diagnosis is important to determine the indications for limited resection. Measurement of the tumor diameter and C/T was useful to determine the indications for limited resection for adenocarcinoma. Limited resection for adenocarcinomas is similar with a larger resection, while the technique should be performed with caution in squamous cell carcinoma and other pathologies.

Background: Diffuse sclerosing variant (DSV) of papillary thyroid carcinoma (PTC) is a rare variant more common among younger patients., Materials and Methods: Excluding patients with microcarcinoma, 5848 patients with PTC underwent initial surgery between 1995 and 2011. Twenty-two patients (0.4 %) were histologically diagnosed with DSV, of whom 20 (91 %) were <45 years old. We compared clinicopathologic characteristics and outcomes between patients with DSV and those with classical PTC <45 years old. Univariate analysis by the Kaplan-Meier method in relation to cause-specific survival (CSS) and disease-free survival (DFS) rates was performed with regard to the following variables: sex; anti-thyroglobulin antibody (TgAb) positivity; presence of distant metastasis; pathological lymph node metastasis; extra-thyroidal invasion; and pathological variant (classical vs. DSV)., Results: The 20 patients with DSV <45 years old comprised 18 females and 2 males. Frequencies of TgAb, pN1b, and local recurrence were higher in the DSV group than in the classical PTC group. Ten-year CSS and DFS rates for PTC patients <45 years old were 99.7 and 88.6 % in the classical PTC group and 100 and 60.5 % in the DSV group. CSS rate did not differ between groups, but DFS rate was significantly lower in the DSV group than in the classical PTC group (p < 0.0001, log-rank test). Multivariate analysis identified DSV group and pN1b as prognostic factors for recurrence in young PTC patients., Conclusions: Most DSV patients were young and had a background of chronic thyroiditis. Outcomes for DSV were very good, but recurrence was more common than in classical PTC.

Background: Total thyroidectomy is well accepted as initial surgery for papillary thyroid cancer (PTC), but the extent of the thyroidectomy remains a matter of controversy. This study was designed to investigate the long-term clinical outcome of PTC patients who had undergone thyroid lobectomy and to elucidate the indications of lobectomy as initial surgery., Methods: The cases of 1,088 PTC patients who underwent thyroid lobectomy with curative intent at Ito Hospital between 1986 and 1995 were analyzed retrospectively in this study. None of the patients had received postoperative radioactive iodine (RAI) ablation therapy. The median follow-up period was 17.6 years. All clinical outcomes, including recurrence and death as a result of PTC or other reasons, were evaluated. To establish the indications for lobectomy as initial surgery for PTC, the potential risk factors, such as age, sex, primary tumor size, extrathyroidal invasion, and clinical lymph node metastasis at the time of the initial surgery, were assessed statistically for associations with recurrence and disease-related death., Results: The remnant-thyroid recurrence-free survival (RT-RFS) rate, the regional- lymph-node recurrence-free survival (L-RFS) rate, and the distant-recurrence-free survival (D-RFS) rate as of 25 years after surgery were 93.5, 90.6, and 93.6%, respectively. The cause-specific survival (CSS) rate at 25 years was 95.2%. Univariate and multivariate analyses showed that none of the factors assessed were significantly associated with the RT-RFS rate. Tumor size, clinical lymph node metastasis, and extrathyroidal invasion were significantly associated with the L-RFS rate. The D-RFS and CSS rates were both significantly lower in the group of patients who were aged 45 years old or older, the group whose tumors were larger than 40 mm, and the group with extrathyroidal invasion. Based on the above findings, we classified the patients into four groups according to age <45 or ≥ 45 years, tumor size ≤ 40 or >40 mm, whether clinical lymph node metastasis was present, and whether extrathyroidal invasion was present. None of the patients without any of these four risk factors died of PTC. On the other hand, 22 patients who died of PTC were positive for one or more of these four factors., Conclusions: The long-term clinical outcome of the PTC patients who had been treated by lobectomy without RAI ablation was excellent. Based on the above results, we concluded that lobectomy is a valid alternative to total thyroidectomy for the treatment of PTC patients who are younger than aged 45 years, whose tumor diameter is 40 mm or less, and who do not have clinical lymph node metastasis or extrathyroidal invasion.

The purpose of this study was to evaluate the clinical value of bilateral breast magnetic resonance (MR) imaging (MRI) in patients showing suspicious microcalcifications on mammography and negative ultrasound findings. Fifty patients underwent MRI before stereotactic vacuum-assisted breast biopsy (SVAB). MR findings were classified into five types for interpretation, and types 4 and 5 were considered malignant. SVAB revealed 13 carcinomas and 37 benign lesions. Malignant lesions were more frequently found in cases of positive MRI diagnoses than in negative MRI diagnoses (P < 0.001). Mammography had a sensitivity of 100%, a specificity of 24% and an accuracy of 44%, whereas mammography plus MRI had a sensitivity of 85%, a specificity of 100% and an accuracy of 96%. In the evaluation of mammographically detected microcalcifications, bilateral breast MRI is of good diagnostic value and may alter the indications for SVAB.

Integration of human papillomavirus DNAs into the host genome is crucial to the development of cervical cancer. Overexpression of the P16 protein has been reported in cervical intraepithelial neoplasia (CIN) as well as cervical cancer. Such molecular biomarkers have been utilized for ancillary testing of liquid-based cytology specimens; however, their clinical application remains controversial. To detect CIN 2 or more advanced lesions, 153 liquid-based cytology (LBC) specimens were investigated to determine the physical status of the human papillomavirus (HPV) DNA by in situ hybridization (ISH) and to detect overexpression of the P16 protein by immunocytochemistry combined with HPV genotyping by polymerase chain reaction. The combination of ISH, P16 immunocytochemistry, and LBC showed high sensitivity (89.3%) as well as high specificity (92.6%). We confirmed the usefulness of P16 immunocytochemistry combined with ISH and HPV genotyping as ancillary molecular-biological tests of LBC specimens for identifying patients at high risk of cervical cancer.

Goiters were often associated with iodine deficiency in European mountain areas, with some goiters being quite disfiguring. However, some goiters seem not to be related to iodine deficiency. One of the types of goiter that are unrelated to iodine deficiency is the disease described by Hakaru Hashimoto in 1912. Hashimoto described it as a special characteristic of a new type of lymphomatous thyroid tumor in Japan, and this entity was recognized as an autoimmune disease of the thyroid many years later. Hashimoto published his article in a German journal because that was the scientific language of the time, and he thought that writing in German would make the work more widely available around the world. Patients with Hashimoto's thyroiditis are usually asymptomatic, and some patients develop goiters with or without hypothyroidism. The goiters and hypothyroidism usually respond to treatment with thyroid hormone. The dose of thyroid hormone must be carefully titrated because there may be autonomous thyroid function resulting from thyroid-stimulating antibodies despite the hypothyroid state.

We report a case of relapsing pancreatitis in familial adenomatous polyposis (FAP) with severe duodenal adenomatosis (Spigelman's stage IV). A 58-year-old man who had undergone total colectomy for FAP 18 years earlier was hospitalized for carcinoma arising from the residual rectum. He had experienced several episodes of upper abdominal pain and ultrasonography and computed tomography (CT) showed diffuse calcification of the atrophic pancreas, suggestive of chronic pancreatitis. He had severe diabetes mellitus, but had no symptoms of pancreatic exocrine dysfunction. Upper endoscopy showed multiple duodenal adenomas including carcinoma involving the papilla of Vater. To remove these duodenal adenomas and ampullary carcinoma and prevent recurrent pancreatitis, we performed pancreaticoduodenectomy. On pathologic examination, the major duodenal papilla was completely obstructed by the carcinoma, and the minor papilla was also involved by the adenoma. The patient has no evidence of disease and has experienced no pancreatitis in 3 years of follow-up.

We resected a fist-sized, solitary fibrous tumor of the pleura (SFTP) with a minute malignant component, following percutaneous embolization of its feeding artery. The tumor had macroscopic characteristics of a benign SFTP, and most parts of it were microscopically benign. However, further careful pathological examination revealed a minute malignant component in its periphery. We report this case to show that large and mostly benign SFTPs may contain malignant components, which can be overlooked. Thus, large SFTPs should be resected in consideration of this possibility.

Signet-ring cell carcinoma (SRCC) of the ampulla of Vater is uncommon, and only 13 cases have been previously described. We herein report a rare case of a 43-year-old woman with SRCC in the ampulla of Vater. Although this histologic type of cancer generally predicts a poor prognosis elsewhere in the gastrointestinal tract, the present patient has survived with no evidence of recurrence for 7.5 years. The patient was hospitalized for pruritus and jaundice. She underwent a pancreaticoduodenectomy with an extended lymphadenectomy for ampullary carcinoma. This neoplasm was classified as AcdbBi, 2.0 x 1.8 cm, ulcerative type, Panc(0), Du(2), T(2)N(0)M(-), Stage II according to the Japanese Classification on Cancer of the Biliary Tract. Unfortunately, previous reports of ampullary SRCC have been limited to short-term follow-ups with a median period of only 12 months (range, 6-134 months), and long-term survival (more than 5 years) was only documented in two cases without lymph node metastasis (including the present case). In conclusion, the experience gained in the present and previous cases suggests that long-term survival is possible following a curative resection in selected patients with ampullary SRCC without nodal involvement. Due to the lack of sufficient evidence, additional reports are warranted to determine whether SRCC also portends a poor prognosis in patients with ampullary cancer.

We report a rare case of intrahepatic cholangiocarcinoma associated with old infestation of Schistosoma japonicum. The patient was a 76-year-old Japanese man who had lived his childhood in an endemic area of this parasite. He presented with jaundice and computed tomography showed a 4-cm, hypodense tumor in segment VIII of the liver. Microscopically, the resected mass was composed of well-differentiated adenocarcinoma cells. Fibrosis and inflammation were seen around the dilated peripheral portal veins embolized with dead S. japonicum eggs. Our search of the literature found only one other case of cholangiocarcinoma coincident with S. japonicum, suggesting that it is not a risk factor for cholangiocarcinoma, although the inflammation and fibrosis caused by the S. japonicum eggshells may predispose to carcinogenesis. However, there is no evidence supporting this hypothesis. More data are necessary to evaluate the differences in clinicopathological findings between cholangiocarcinoma concomitant with S. japonicum and the usual type of cholangiocarcinoma.

The occurrence of non-neoplastic, scattered endocrine cells in pancreatic ductal adenocarcinoma (DAC) is thought to be a general phenomenon. Conversely, neoplastic endocrine differentiation (NED) of pancreatic DAC is extremely unusual. We report a case of NED in a metastatic lymph node from pancreatic DAC. This case is distinct because the main tumor of the pancreas was composed purely of DAC without endocrine differentiation, and the NED was found in only one of four metastatic peripancreatic lymph nodes. To our knowledge, no other such case has ever been reported. The patient was a 61-year-old woman who underwent pylorus-preserving pancreaticoduodenectomy for pancreatic head cancer. Some authors reported that pancreatic DAC with endocrine differentiation was associated with a better prognosis than DAC without endocrine differentiation. However, more cases must be studied to investigate the impact of NED of metastatic lymph nodes in pancreatic DAC.

Introduction: Intraoperative detection of sentinel nodes (SNs) has been used clinically to predict regional lymph node (LN) metastasis in patients with breast cancer and malignant melanoma. Intraoperative lymphatic mapping and SN biopsy can potentially be combined with minimally invasive surgery. However, few reports have demonstrated the validity of SN biopsy during laparoscopic gastrectomy. The aim of this study was to investigate the feasibility and accuracy of laparoscopic lymphatic mapping in predicting LN status in patients with gastric cancer., Methods: A total of 35 patients with gastric cancer diagnosed preoperatively as T1, N0 were enrolled. Endoscopic injection of technetium-99m-radiolabeled tin colloid was completed 16 hours before surgery, and radioactive SNs were identified with a gamma probe intraoperatively. Isosulfan blue dye was injected endoscopically during the operation. Laparoscopy-assisted gastrectomy with LN dissection was performed. All resected LNs were evaluated by routine pathology examination., Results: SNs were detected in 33 (94.3%) of 35 patients. The mean number of SNs was 3.9, and the diagnostic accuracy according to SN status was 97.0% (32/33), as one patient with a false-negative result was observed. The patient with the false-negative specimen was finally diagnosed as having advanced gastric cancer with invasion into the proper muscular layer and severe lymphatic vessel invasion, causing destruction of normal lymphatic flow by the tumor., Conclusions: Radio-guided SN mapping during laparoscopic gastrectomy is an accurate diagnostic tool for detecting lymph node metastasis in patients with early-stage gastric cancer. Validation of this method requires further studies on technical issues, including indications, tracers, methods of lymph node retrieval, and diagnostic modalities of metastasis.

We report a rare case of hepatic inflammatory pseudotumor (IPT) after a hepatitis B virus (HBV) infection. Early contrast enhancement on computed tomography (CT) with a washout phenomenon at the delayed phase, and depleted Kupffer cell function on superparamagnetic iron oxide (SPIO)-enhanced magnetic resonance imaging (MRI) suggested hepatocellular carcinoma (HCC). However, the lack of a tumor capsule, absence of liver cirrhosis, and normal serum levels of alpha-fetoprotein and PIVKA-II (protein induced by vitamin K absence; descarboxyprothrombin) contradicted this diagnosis. We excised the tumor to exclude malignancy, and the histopathological diagnosis was IPT. Recent evidence suggests that this entity has changed from an extremely rare pathology to an established disease. Thus, IPT should be considered in the differential diagnosis of a liver mass with an infectious-inflammatory antecedent. Although surgery is not mandatory, surgical removal is recommended if there is a possibility of malignancy. Further investigations are warranted to elucidate the mechanisms of IPT developing after an HBV infection.

Extraskeletal tumors containing multinucleated, osteoclast-like giant cells (OGCs) are uncommon. These neoplasms are most frequently reported in the breast and pancreas. Recently, some authors have suggested that carcinomas containing OGCs may represent a distinct clinicopathological entity with a more favorable prognosis. Occurrence in the gallbladder is extremely rare, with only one previous case. We report here on an additional case of gallbladder carcinoma with an infiltrate of OGCs. A 72-year-old woman presented with postprandial abdominal pain and was found to have a mass in the body of the gallbladder with direct liver invasion. Histological examination showed an adenosquamous carcinoma with an infiltrate of benign OGCs. Immunohistochemical analysis demonstrated that the giant cells were of histiocytic origin. The patient survived for 6 years without evidence of recurrence. This case adds to a small body of literature on gallbladder carcinoma with OGCs. Further studies are required to clearly define the prognostic significance of these giant cells in gallbladder cancer and the differences between adenosquamous carcinoma with OGCs and other gallbladder carcinomas (such as adenocarcinoma and squamous cell carcinoma) with those cells.

Undifferentiated spindle-cell carcinoma (SpCC) of the gallbladder is extremely rare. There is very little information available regarding the characteristics and treatment of this disease. We herein report the unique case of a 76-year-old female patient with a primary SpCC of the gallbladder that presented as a liver tumor. Preoperative radiologic examinations showed a 5-cm liver tumor around the gallbladder bed, and irregular thickening of the gallbladder wall. The patient underwent en-bloc resection of the gallbladder and segments 4b and 5 of the liver (including the liver tumor). Microscopic findings revealed that both lesions consisted mainly of a sarcomatous spindle-shaped component. Small foci of well-differentiated adenocarcinoma cells were identified in the gallbladder mucosa. There was a gradual transition between the two different components, thereby implying that these two cell types had a common origin. Immunohistochemical studies showed that the spindle-shaped cells were epithelial in nature. The patient's postoperative course was uneventful. However, she died of recurrent liver disease 6 months after the surgery. In conclusion, we surmised that the sarcomatous spindle cells originated from a carcinomatous component in the gallbladder mucosa through dedifferentiation. Further studies are needed to better understand the characteristics of this deadly tumor, and to establish an effective therapy for it.

A 69-year-old man underwent decortication and latissimus dorsi muscle transposition for the treatment of chronic empyema in January 2001. The empyema recurred in March 2002, and open drainage was thus started in July 2002. In February 2003, massive hemorrhaging from the thoracic cavity occurred. Tamponade and hemostasis were performed immediately, and angiography revealed bleeding from the pulmonary artery (PA). After identification of the bleeding point, surgical hemostasis was successfully achieved following PA occlusion with a Swan-Ganz thermodilution catheter.

We report a case of a 79-year-old woman with an unusual salivary gland tumor that developed at the junction between the soft and hard palates. The tumor consisted of sialadenoma papilliferum (SP) with areas of an epithelial-myoepithelial carcinoma (EMC) component and a high-grade carcinoma component. There were also transitional regions among the SP, the EMC and the high-grade carcinoma components. The high-grade carcinoma component, which was similar to invasive micropapillary carcinoma of the breast, infiltrated into the right parapharyngeal space and metastasized to the lungs and cervical vertebrae. The high-grade carcinoma cells were positively immunostained for p53 protein. SP has been considered to be a benign tumor with exceptionally good prognosis, and, to the best of our knowledge, there has never been a confirmed case of malignant SP. This is the first report of SP with a definite malignant component.

We report a case of adenolipoma of the thyroid gland, which is very unusual because thyroid adenoma rarely contains mature adipose tissue. A 55-year-old Japanese woman presented with a 1-month history of a neck mass. A blinded fine-needle aspiration biopsy showed benign follicular cells with no adipose cells, and we performed a left hemithyroidectomy. The specimen measured 7.0 x 4.4 cm and weighed 59.9 g. The cut surface of the tumor revealed a solid yellowish mass, and hematoxylin-eosin staining showed that the solid tumor was well separated from the adjacent thyroid tissue by a thin fibrous capsule. The tumor was found to be follicular adenoma composed of epithelial cells arranged in monotonous microfollicular patterns, intermingled with mature adipose tissue. No adipose tissue was found outside the tumor, and there were no signs of amyloid deposits in the tumor or adjacent thyroid tissue. The pathological diagnosis was adenolipoma of the thyroid gland. We discuss the pathogenesis of this entity and review the previously documented cases.

We reviewed 188 cases of Hürthle cell tumor of the thyroid (HCT) between 1982 and 1996. There were 160 women and 28 men with a mean age of 51.8 years. Thirty-one of the patients had cancer, and the others had adenoma. Age, size of the primary tumor, and preoperative thyroglobulin level were not significantly different in the cancer and adenoma patients. The gender ratio, however, was significantly different (p < 0.05). Recurrent HCT was observed in three patients with adenoma. Two patients had subcutaneous recurrence (suspected implantation), and the other patient had recurrence in the residual thyroid gland. All patients with recurrence of adenoma underwent partial lobectomy at the initial operation. Three cancer patients had recurrent disease. Locoregional recurrence was observed in one patient and distant metastases in two patients (lung in one, lung and bone in one). One of the patients with distant metastasis died from the disease, and the other is alive with the disease. Tumor implantation was observed in patients with adenoma, so intraoperative handling of the tumor requires care. It also means that this tumor, even though benign, is aggressive in terms of proliferative activity. All patients with Hürthle cell tumor should be treated by total lobectomy at least. The outcome of the cancer patients was not as poor as in previous reports.

Ectopic hamartomatous thymoma (EHT) is a rare benign neoplasm. Since it was named by Rosai et al. in 1984, 24 cases have been reported. We herein report two cases of EHT, one of which presented with massive myoid cells, and review the literature related to EHT. Both of our cases displayed the typical features of EHT: (1) nests of epithelial cells, including solid, cystic, or glandular epithelial islands; (2) spindle cells dominating the microscopic picture; and (3) adipose cells which intermingle haphazardly to impart a hamartomatous quality to the tumor. In this paper, we observed massive myoid cells and the transition from spindle epithelial cell to myoid cell in one of our cases. Immunohistochemical examinations showed that the main component of EHT, spindle cells, was positive for cytokeratin and epithelial membrane antigen (EMA). Intriguingly, the myoid cells simultaneously expressed cytokeratin, EMA, myoglobin, and creatine kinase-mm, suggesting that myoid cells may originate from epithelial cells and are an intermediate state between epithelial cells and muscular cells.

In situ hybridization (ISH) of the expression of matrix metalloproteinase-1 (MMP-1) in areas of local invasion of head and neck tumours was performed. Expression of MMP-1 mRNA was found in stromal inflammatory cells adjacent to the tumour nests, apparently in eosinophils. MMP-1 mRNA expression was seen only in cases with moderate or greater stromal eosinophilia. MMP-1 mRNA was detected in benign papilloma and verrucous carcinoma. In squamous cell carcinomas, expression of the gene was detected only in well-differentiated cases. Expression of MMP-1 mRNA was not related to the grade of malignancy, and appeared in stromal eosinophils, suggesting to us that it is involved in a remodelling process in the reaction of the host to tumour invasion. ISH examination of the expression of interleukin-5 (IL-5), the activating factor for eosinophils, was also performed. In the tumour, its expression was consistent with the location of eosinophils, as with MMP-1 mRNA, suggesting an autocrine mechanism.

Collagenolytic proteinases play an important pathological role in the invasion and metastasis of cancer cells. However, little is known about the role of interstitial collagenase (matrix metalloproteinase-1; MMP-1) in this process. To investigate the expression of the MMP-1 gene in cancer tissues, an in situ hybridization study was carried out in gastrointestinal tract cancers (one esophageal cancer, five gastric cancers, and four colorectal cancers), using a 35S-labeled MMP-1 cDNA probe. The MMP-1 gene was expressed in the stromal cells of fibrous tissue around cancer nests, especially at the margin of invasion and/or within the cancer nest; however, no definite expression within cancer cells was observed. Expression of the MMP-1 gene in the stromal cells was more common in well differentiated gastric adenocarcinoma than in poorly differentiated adenocarcinomas. These findings indicate that expression of the MMP-1 gene is greater in stromal cells that are closely associated with cancer cells, suggesting a pathophysiological role of MMP-1 in the invasion and metastasis of cancer cells.