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Extremely well-differentiated gastric-type adenocarcinoma (EWDGA) is a rare type of gastric cancer composed of deceptively bland-looking malignant cells resembling normal foveolar or pyloric epithelium. The histological features of this tumor have not been recognized by many pathologists, and inter-observer variation studies are lacking. Here, we report seven EWDGAs and inter-observer variation of six preoperative biopsies was evaluated by 11 pathologists in a single institute. Based on the pathological diagnosis of the endoscopic biopsy slides, the average rate of definite malignancy diagnosis was 15.2 %, and the overall diagnostic concordance rate was 34.9 % among 11 pathologists. Microscopically, the surface epithelium was preserved and only a few atypical tumor glands were scattered in most endoscopic biopsies. Structural atypia was minimal, and the tumor glands were barely distinguishable from normal glands. Although nuclear atypia was minimal, enlarged nuclei, relatively large glands with irregular shapes, and abundant cytoplasmic mucin were observed in gastric pinch biopsies. In preoperative biopsies, no cases showed p53 overexpression, and Ki-67 labeling index ranged from 3 % to 35 % and was higher compared to non-neoplastic glands in 3 cases. After gastrectomy, four (57.1 %) patients had advanced gastric cancer and three (42.9 %) had lymph node metastasis. Genomic profiling of the four patients revealed mutations of TP53, BRAF, KRAS, STK11, and MDM2/CCND1 amplification. Immunohistochemistry for p53 was not helpful while Ki-67 may be helpful when staining pattern is distinct from the non-neoplastic mucosa. In conclusion, it is challenging to diagnose EWDGA using biopsy specimens. Recognizing and addressing this rare entity will increase diagnostic accuracy to ensure the early diagnosis of cancer., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper, (Copyright © 2024 The Authors. Published by Elsevier GmbH.. All rights reserved.)

A man in his 80s was referred to our hospital with the chief complaint of perianal erosion. Colonoscopy revealed a peripheral flat lesion in the anal canal. Since immunohistological examination showed positive for CK20 and negative for GCDFP15, we made a preoperative diagnosis of anal canal cancer with Pagetoid spread. It was diagnosed as cT1bN0M0, cStage Ⅰ by TNM classification, and laparoscopic abdominoperineal resection with TpTME was performed. Negative biopsy of the perianal skin was confirmed both preoperation and during the operation. The postoperative course was uneventful, and no urinary dysfunction was observed. The patient was discharged 15 days after the operation. The histopathological diagnosis was negative margin. The patient is alive without recurrence 1 year after the operation. Adenocarcinoma of anal canal with Pagetoid spread is rare, and differentiation from Paget's disease is important for determining treatment policy. By conducting a detailed examination of the extent of tumor progression and using TpTME together, it was possible to perform surgery that both secured the CRM and preserved urinary function.

The fifth edition of the World Health Organization (WHO) classification of digestive system tumours was published in 2019. The classification of invasive carcinoma is basically the same as in the fourth edition, but the description of each histological type has been updated, and some rare subtypes such as micropapillary carcinoma, gastric adenocarcinoma of the fundic gland type and undifferentiated carcinoma have been added and explained. Although this classification did not provide specific numerical criteria for the diagnosis of signet-ring cell carcinoma in poorly cohesive carcinoma, an additional study defined signet-ring cell carcinoma as having more than 90% signet-ring cells. The molecular classification of gastric cancer (Epstein-Barr virus-positive type, microsatellite instability type, genomically stable type, chromosomally unstable type) was additionally introduced. Many pages in the present classification have been devoted to precancerous lesions, and this article focuses on foveolar-type adenoma/dysplasia., (© 2021. The Author(s), under exclusive licence to Springer Medizin Verlag GmbH, ein Teil von Springer Nature.)

Introduction: Intestinal resection with lymph node dissection is the current standard treatment for high-risk lower rectal submucosal invasive cancer after local resection; however, surgery affects patients' quality of life due to stoma placement or impaired anal sphincter function. A recent study demonstrated that adjuvant chemoradiation yields promising results., Methods and Analysis: This study aims to confirm the non-inferiority of adjuvant chemoradiation, consisting of capecitabine and concurrent radiotherapy (45 Gy in 25 fractions), measured by 5-year relapse-free survival (RFS), over standard surgery in patients with high-risk lower rectal submucosal invasive cancer after local resection. The primary endpoint is 5 year RFS. The secondary endpoints are 10 years RFS, 5-year and 10-year overall survival, 5-year and 10-year local RFS, 5-year and 10-year proportion of anus-preservation without stoma, Wexner score, low anterior resection syndrome score, adverse events and serious adverse events. During the 5-year trial period, 210 patients will be accrued from 65 Japanese institutions., Ethics and Dissemination: The National Cancer Center Hospital East Certified Review Board approved this study protocol in October 2018. The study is conducted in accordance with the precepts established in the Declaration of Helsinki and Clinical Trials Act. Written informed consent will be obtained from all eligible patients prior to registration. The primary results of this study will be published in an English article. In addition, the main results will be published on the websites of Japan Clinical Oncology Group (www.jcog.jp) and jRCT (https://jrct.niph.go.jp/). As to data curation, it has not been prepared yet., Trial Registration Number: jRCT1031180076., Competing Interests: Competing interests: KS reports grants from reports research funding from Chugai., (© Author(s) (or their employer(s)) 2020. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Background and Aim: Gastric intestinal-type adenocarcinoma with anastomosing glands (IAAG) is characterized by architectural abnormality with frequent anastomosing glands and low-grade cytologic atypia. Clinicopathologic features and long-term outcomes of endoscopic submucosal dissection (ESD) for IAAG remain unclear., Methods: This study included 2828 patients who underwent ESD for early gastric cancers (EGCs) (78 IAAGs [2.6%] and 2893 well-differentiated [WD] or moderately differentiated [MD] EGCs [97.4%]). Clinicopathologic features and short-term and long-term outcomes of ESD for IAAG were reviewed and compared with those for WD or MD EGCs., Results: Gastric IAAGs were larger and more likely to be confined to the lamina propria than WD or MD EGCs. Histological heterogeneity, flat or depressed lesion and lateral resection margin (LRM) involvement were observed with significantly higher frequencies in IAAGs than in WD or MD EGCs. En bloc with R0 resection and curative resection rates of IAAGs were 79.5% and 73.1%, respectively, and both were significantly lower than those of WD or MD EGCs (93.8% and 82.9%). LRM involvement accounted for 57.1% of the non-curative resection cases in gastric IAAGs. Half of IAAGs with LRM involvement had a crawling pattern at tumor periphery. Among patients undergoing curative ESD for IAAG, no recurrences occurred during a median 52 months of follow-up. No lymph node metastasis was found in any of IAAG patients undergoing additional surgery after ESD., Conclusions: Gastric IAAGs have distinct clinicopathologic features from WD or MD EGCs. Given the favorable long-term outcomes after curative resection, ESD can be indicated for early gastric IAAGs., (© 2019 Journal of Gastroenterology and Hepatology Foundation and John Wiley & Sons Australia, Ltd.)

Epstein-Barr virus (EBV)-associated gastric carcinoma (EBVGC) is defined as a neoplasm comprising monoclonal proliferation of EBV-infected gastric epithelial cells. Although the typical histology is gastric carcinoma with lymphoid stroma (GCLS), the histologic features of the tumor vary. We report herein the case of a 78-year-old man with multiple simultaneous EBVGCs revealing different histopathologic morphologies; one was mixed adenoneuroendocrine carcinoma (MANEC), and the other was GCLS. Both tumor types exhibited positive results for EBV in situ hybridization. To the best of our knowledge, this represents the first report of EBVGC showing neuroendocrine differentiation. Immunohistochemistry also revealed a loss of gastrointestinal features, including CDX2, MUC5AC, and MUC6 expression, among tumor cells from the neuroendocrine component of the MANEC. We describe the pathologic features of this rare neoplasm and discuss the mechanisms underlying the neuroendocrine differentiation of EBVGC cells, along with providing a brief review of the literature., (© 2017 Japanese Society of Pathology and John Wiley & Sons Australia, Ltd.)

Cancer invasion of the lamina propria is an important pathological finding. However, the clinicopathologic features and diagnostic accuracy of intramucosal carcinoma assessment in colorectal carcinoma (CRC) are unknown. In this study, intramucosal CRCs were reviewed in institutions affiliated with the Japanese Society for Cancer of the Colon and Rectum, and 32 cases with invasion of the lamina propria were identified. Next, a consensus meeting was held to select cases with a high consensus about the presence of invasion, which were reviewed by one Western pathologist for confirmation. In addition to clinicopathologic evaluation, concordance was assessed for diagnosis and histologic findings. During the consensus meeting, 3 cases were found to show ambiguous features such that it was unclear whether there was intramucosal or submucosal invasion, and 7 cases were judged to have invasion of the lamina propria by more than 75% of the pathologists. A poorly differentiated adenocarcinoma and a signet ring cell carcinoma were diagnosed unanimously. Concordance in diagnosis and detection of characteristics of invasion of the lamina propria proved to be only poor to fair. Single or small clusters of cells and atypical or complex glandular arrangements that are beyond normal mucosal architecture were detected more frequently in the 7 high-consensus tumors. Desmoplasia and marked inflammation were detected more often in cases characterized as ambiguous. Intramucosal CRCs with invasion of the lamina propria constituted 5.1% of the surgically resected high-grade intramucosal epithelial dysplastic/neoplastic lesions, and stromal infiltration of single or small clusters of cells is the best objective criterion of invasion., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Background: The invasive tumour front may provide prognostic information. We examined the relationship between the presence of cancer stem cells (CSCs) at the invasive tumour front and prognosis in gastric cancer (GC)., Methods: CD44 is a CSC marker; accordingly, CD44 standard (CD44s), CD44 variant-6 (CD44v6), and CD44 variant-9 (CD44v9) expression were examined in 123 resected primary GCs and the clinical significance of CSCs at the invasive tumour front was analysed., Results: Thirteen (10.6%), 79 (64.2%), and 47 (38.2%) GCs were CD44s-, CD44v6-, and CD44v9-positive, respectively. Patients with CD44-positive expression at the invasive tumour front had significantly poorer disease-specific survival than those with negative expression (CD44s: P<0.00001, CD44v6: P=0.013, CD44v9: P=0.0002). CD44s expression at the invasive tumour front was an independent prognostic factor in resectable GC patients (hazard ratio=3.13; 95% confidence interval, 1.09-9.01; P=0.035) and was significantly associated with peritoneal (P<0.001), lymphatic (P<0.001), and haematogenous recurrences (P=0.008). In addition, the number of CD44 isoforms expressed in cancer cells at the invasive tumour front was associated with patient prognosis. No conventional clinicopathological factors were independently associated with CD44 expression at the invasive tumour front., Conclusions: CD44-positive cancer stem-like cells at the invasive tumour front indicate poor survival and can be a unique biological prognostic factor for GC.

Background: Gastro-oesophageal adenocarcinomas rarely metastasize to the central nervous system (CNS). The role of the human epidermal growth factor receptor 2 (HER2) in patients with these cancers and CNS involvement is presently unknown., Patients and Methods: A multicentre registry was established to collect data from patients with gastro-oesophageal adenocarcinomas and CNS involvement both retrospectively and prospectively. Inclusion in the study required a predefined clinical data set, a central neuro-radiological or histopathological confirmation of metastatic CNS involvement and central assessment of HER2 by immunohistochemistry (IHC) and in situ hybridisation (ISH). In addition, expression of E-cadherin and DNA mismatch repair (MMR) proteins were assessed by IHC., Results: One hundred patients fulfilled the inclusion criteria. The population's median age was 59 years (interquartile range: 54-68), of which 85 (85%) were male. Twenty-five patients were of Asian and 75 of Caucasian origin. HER2 status was positive in 36% (95% CI: 26.6-46.2) of cases. Median time from initial diagnosis to the development of brain metastases (BMets) or leptomeningeal carcinomatosis (LC) was 9.9 months (95% CI: 8.5-15.0). Median overall survival from diagnosis was 16.9 months (95% CI: 14.0-20.7) and was not related to the HER2 status. E-cadherin loss was observed in 9% of cases and loss of expression in at least one DNA MMR proteins in 6%., Conclusions: The proportion of a positive HER2 status in patients with gastro-oesophageal adenocarcinoma and CNS involvement was higher than expected. The impact of anti-HER2 therapies should be studied prospectively.

An 80-year-old man was under annual surveillance esophagogastroduodenoscopy after endoscopic submucosal dissection (ESD) for early gastric cancer (EGC). Two years after the initial ESD, a 0-IIc type metachronous EGC lesion, 8 mm in size, without an ulcer scar, was found in the gastric antrum. The estimated tumor depth was up to the mucosa, and biopsy revealed well and poorly differentiated adenocarcinoma. ESD was performed for this lesion and en bloc resection with negative margins was achieved. Histopathological examination revealed an adenosquamous carcinoma 8 mm in size invading the deep submucosal layer (1600 μm), with lymphovascular invasion, consistent with the diagnosis of non-curative resection. Additional gastrectomy was recommended for this patient; however, two months after the ESD, preoperative computed tomography revealed multiple liver metastases, and the patient was considered as an unsuitable candidate for surgical resection. Systemic chemotherapy was therefore started; however, the patient died of gastric cancer 27 mo after the second ESD. Early gastric adenosquamous carcinoma localized to the mucosa and submucosa is extremely rare and its clinical behavior is not well known. The present report is very significant in that it underscores the distinct possibility of gastric adenosquamous carcinoma being very aggressive and fatal even when detected at an early cancer.

Background: Heterotopic gastric-type epithelium, including gastric foveolar metaplasia (GFM) and gastric heterotopia (GH), is a common finding in duodenal biopsy specimens; however, there is still controversy regarding their histogenetic backgrounds., Methods: We analysed a total of 177 duodenal lesions, including 66 GFM lesions, 81 GH lesions, and 30 adenocarcinomas, for the presence of GNAS, KRAS, and BRAF mutations., Results: Activating GNAS mutations were identified in 27 GFM lesions (41%) and 23 GH lesions (28%). The KRAS mutations were found in 17 GFM lesions (26%) and 2 GH lesions (2%). A BRAF mutation was found in only one GFM lesion (2%). These mutations were absent in all 32 normal duodenal mucosa specimens that were examined, suggesting a somatic nature. Among the GFM lesions, GNAS mutations were more common in lesions without active inflammation. Analyses of adenocarcinomas identified GNAS and KRAS mutations in 5 (17%) and 11 lesions (37%), respectively. Immunohistochemically, all the GNAS-mutated adenocarcinomas diffusely expressed MUC5AC, indicating gastric epithelial differentiation., Conclusions: A significant proportion of GFM and GH harbours GNAS and/or KRAS mutations. The common presence of these mutations in duodenal adenoma and adenocarcinoma with a gastric epithelial phenotype implies that GFM and GH might be precursors of these tumours.

Aim: To analyze the mismatch repair (MMR) status and the ARID1A expression as well as their clinicopathological significance in gastric adenocarcinomas., Methods: We examined the expressions of MMR proteins and ARID1A by immunohistochemistry in consecutive 489 primary gastric adenocarcinomas. The results were further correlated with clinicopathological variables., Results: The loss of any MMR protein expression, indicative of MMR deficiency, was observed in 38 cases (7.8%) and was significantly associated with an older age (68.6±9.2 vs 60.4±11.7, P<0.001), a female sex (55.3% vs 31.3%, P=0.004), an antral location (44.7% vs 25.7%, P=0.021), and a differentiated histology (57.9% vs 39.7%, P=0.023). Abnormal ARID1A expression, including reduced or loss of ARID1A expression, was observed in 109 cases (22.3%) and was significantly correlated with lymphatic invasion (80.7% vs 69.5%, P=0.022) and lymph node metastasis (83.5% vs 73.7%, P=0.042). The tumors with abnormal ARID1A expression more frequently indicated MMR deficiency (47.4% vs 20.2%, P<0.001). A multivariate analysis identified abnormal ARID1A expression as an independent poor prognostic factor (HR=1.36, 95%CI: 1.01-1.84; P=0.040)., Conclusion: Our observations suggest that the AIRD1A inactivation is associated with lymphatic invasion, lymph node metastasis, poor prognosis, and MMR deficiency in gastric adenocarcinomas.

Background and Objectives: The optimal surgical procedure for gastric remnant carcinoma (GRC) remains debatable. The aim of this study was to retrospectively evaluate the surgical treatments for T2-4 GRC developing after distal gastrectomy for gastric cancer., Methods: Between 1970 and 2012, a total of 50 patients underwent R0 resection for T2-4 GRC. The clinicopathologic features, therapeutic methods, and follow-up data of these patients were reviewed., Results: The tumor was located at a non-anastomotic site of the remnant stomach in 43 of the 50 patients. Total gastrectomy was performed in 48 patients and partial gastrectomy was in two patients. Lymph node metastasis was found in 19 patients. Major postoperative complications occurred in 16 patients. The overall 1-, 3-, and 5-year survival rates of the 50 patients were 90%, 66%, and 44%, respectively. Presence of small intestinal or esophageal infiltration and postoperative complications was independently associated with poorer survival. Dissection of the perigastric and splenic hilar/artery nodes was found to have potential therapeutic benefit., Conclusions: Surgical resection for T2-4 GRC developing after distal gastrectomy for gastric cancer can be invasive, but is feasible and effective. Total gastrectomy with splenectomy is one of the recommendable procedures for this disease., (© 2014 Wiley Periodicals, Inc.)

HER2 protein overexpression and gene amplification are important biomarkers for identifying gastric cancer patients who may respond to HER2-targeted therapy using trastuzumab. The aim of this study was to evaluate the concordance between HER2 protein expression and gene amplification in both surgically resected tumors and matched biopsy specimens of gastric cancer. Formalin-fixed, paraffin-embedded sections of 207 surgically resected tumors and 158 biopsy specimens from 207 cases of invasive intestinal-type gastric cancer were analyzed. Protein expression was assessed using immunohistochemistry and graded by the modified scoring criteria for gastric cancer. Gene amplification was evaluated by fluorescence in situ hybridization (FISH). HER2 overexpression was observed in 17 % of both surgically resected tumors (35/207) and biopsy specimens (26/158). HER2 gene amplification was detected in 31 % (61/200) of surgically resected tumors and 32 % (47/147) of biopsy specimens. Except for immunohistochemistry (IHC) equivocal (2+) cases, the concordance rates between IHC and FISH was 90.9 % in surgically resected tumors and 90.2 % in biopsy specimens. In IHC 2+ cases, the rate of HER2 gene amplification was 56 and 38 % in surgically resected tumors and biopsy specimens, respectively. IHC-FISH discordance was mainly due to intratumoral heterogeneity and low-level gene amplification. The concordance rate of IHC results between surgically resected specimens and the corresponding biopsy specimen was 57.0 % (κ = 0.224), and in discordant cases, HER2 positivity in biopsies and HER2 negativity in surgically resected tumors were most common. The concordance rate of FISH results between surgically resected tumors and biopsy specimens was 72.7 % (κ = 0.313). Polysomy 17 was detected in 5.5 and 7.5 % of surgically resected tumors and biopsy specimens and significantly correlated with IHC score, but polysomy 17 could explain one IHC score 3+ and FISH-negative tumor only. Although high concordance rates between HER2-protein expression and gene amplification were observed in both surgically resected tumors and biopsy specimens, the agreement levels were evaluated to be fair. Polysomy 17 was infrequent and seemed to have limited impact on gastric HER2 testing. Further investigations are required for an appropriate biopsy method to reduce false results of HER2 testing and to clarify the clinical significance of intratumoral heterogeneity in HER2 status.

Background: Lung adenocarcinoma with morule-like components is an unusual variant of lung adenocarcinoma, comprising uniform, tightly packed spindle-shaped cells, which fill the lumen of the glandular structures of the carcinoma. The aim of the study was to outline the clinicopathologic features of this variant., Patients and Methods: We examined a series of 904 surgically resected adenocarcinomas. We defined morule-like components as small buds of spindle-cell proliferation in the tumor lumen of the glandular structures of the carcinoma and calculated their proportion of total tumor mass. Targeted genotyping was performed for KRAS, EGFR, HER2, and BRAF. ALK rearrangements were analyzed immunohistochemically. Immunopositive cases were confirmed using RT-PCR and/or FISH., Results: We detected 17 cases of adenocarcinoma with morule-like components. This variant, representing only 1.9% was associated with unfavorable outcomes and a mutation in the EGFR. Histologic examination revealed adenocarcinoma with morule-like components accounting for 5-50% of tumors. Among the morule-like components, 10 (58.8%) of the 17 samples showed intracytoplasmic lumina formation containing eosinophilic mucinous material. The presence of micropapillary components in adenocarcinoma with morule-like components suggests that morule-like components could be merely excessive growth of the micropapillary pattern. However, our results indicated no statistical differences in the MIB-1 indices of the morule-like components and the adjacent tumor components or the micropapillary components. The univariate and multivariate analyses revealed a correlation between the presence of a morule-like components and an unfavorable outcome., Conclusions: Our study clearly indicated that adenocarcinoma with morule-like components is distinct unfavorable prognostic and predictor for EGFR mutation., (Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.)

The prevalence of gastric cancer associated with Lynch syndrome (LS) is highly variable, and the underlying histologic pathway or molecular mechanisms remain unclear. From 1995 to 2012, 15 patients had been treated for both gastric and colonic adenocarcinomas and diagnosed as LS. In all cases, pathologic review, immunohistochemical analysis for mismatch-repair proteins, and microsatellite instability (MSI) tests were performed. To confirm LS, germline mutation tests and multiplex ligation-dependent probe amplification were performed. All gastric and colonic carcinomas were MSI-high and lost expressions of MLH1/PMS2 in 11 (73%) cases and MSH2/MSH6 in 4 (27%) cases. Remarkably, in a patient with LS and germline mutation of MLH1 gene, pyloric gland adenoma (PGA) transformed to adenocarcinoma during follow-up. In 2 additional cases, PGA was found adjacent to advanced gastric cancers. All PGAs in LS patients were MSI-high and lost expression of mismatch-repair proteins (MLH1/PMS2 in 2 cases and MSH2/MSH6 in 1 case), whereas none of the 14 sporadic PGAs was MSI-high or had lost expression of mismatch-repair proteins. On the basis of these observations, although very rare, we suggest the possibility that PGA may be a precursor lesion to gastric adenocarcinoma in LS and that the mismatch-repair deficient pathway of carcinogenesis is involved early in the gastric carcinogenesis pathway.

The recent discovery and characterization of an oncogenic ROS1 gene fusion in a subset of lung cancers has raised significant clinical interest because small molecule inhibitors may be effective to these tumors. As lung cancers with ROS1 rearrangements comprise only 1-3% of lung adenocarcinomas, patients with such tumors must be identified to gain optimal benefit from molecular therapy. Recently, immunohistochemical analyses using a novel anti-ROS1 rabbit monoclonal antibody (D4D6) have shown promise for accurate identification of ROS1-rearranged cancers. To validate this finding, we compared the immunostaining results of tissue microarrays (TMAs) containing 17 ROS1-rearranged and 253 ROS1-non-rearranged lung carcinomas. All 17 ROS1-rearranged cancers showed ROS1 immunoreactivity mostly in a diffuse and moderate-to-strong manner with an H-score range of 5-300 (median, 260). In contrast, 69% of ROS1-non-rearranged cancers lacked detectable immunoreactivity, whereas the remaining 31% showed reactivity mainly in a weak or focal manner. The H-score for the entire ROS1-non-rearranged group ranged from 0 to 240 (median, 0). The difference in H-score between the two cohorts was statistically significant, and the H-score cutoff (≥150) allowed optimal discrimination (94% sensitivity and 98% specificity). Similar but slightly less-specific performance was achieved using the extent of diffuse (≥75%) staining or ≥2+ staining intensity as cutoffs. CD74-ROS1 and EZR-ROS1 fusions were significantly associated with at least focal globular immunoreactivity and plasma membranous accentuation, respectively, and these patterns were specific to ROS1-rearranged cases. Although full-length ROS1 is expressed in some ROS1-non-rearranged cases, we showed that establishment of an optimal set of interpretative criteria makes ROS1 immunohistochemistry a valuable method to rapidly and accurately screen lung cancer patients for appropriate molecular therapy.

Background: The accurate diagnosis of lymph node (LN) metastasis is important for making treatment decisions for gastric cancer patients. This multicenter study evaluated the clinical performance of the one-step nucleic acid amplification (OSNA) assay (Sysmex Corp.), an automated system that detects cytokeratin 19 (CK19) mRNA, in detecting LN metastases in gastric cancer patients., Methods: LNs retrieved from patients who had undergone gastric cancer surgery at one of the four Japanese hospitals involved in this study were divided into blocks at 2-mm intervals. Alternate blocks were examined with the OSNA assay and the remaining blocks were assessed histologically., Results: A total of 394 LNs from 61 patients were examined. The concordance rate between the OSNA assay and the histological examination was 0.942 (95 % CI, 0.914-0.963). Sensitivity and specificity of the OSNA assay compared to the histological examination were 0.833 (95 % CI, 0.707-0.921) and 0.959 (95 % CI, 0.932-0.977), respectively. Discordant results were observed in 23 LNs (5.8 %), and these were mainly the result of tissue allocation bias and/or low CK19 protein expression., Conclusion: The OSNA assay can detect lymph node metastases in gastric cancer patients as accurately as the histological examination of blocks sectioned at 2-mm intervals. The OSNA assay is a useful tool for the intraoperative diagnosis of LN metastasis in gastric cancer patients.

Background and Study Aims: After noncurative endoscopic submucosal dissection (ESD) for differentiated-type early gastric cancer (EGC), close observation is often preferred when a cancer-positive lateral margin is the only noncurative factor. However, sometimes recurrence is found during the observation period. This study aimed to examine risk factors for recurrent cancer based on the long-term clinical outcomes after noncurative ESD in which the only noncurative factor was a cancer-positive lateral margin., Patients and Methods: Among 3784 EGCs (3316 patients) treated by ESD between 1997 and 2010, 77 noncurative differentiated-type EGCs (75 patients) were retrospectively analyzed after meeting the following inclusion criteria: 1) the only noncurative factor was a cancer-positive lateral margin; 2) close observation was selected after the ESD; and 3) > 1 year follow-up after ESD., Results: Locally recurrent cancer was found in 10 lesions within a median follow-up period of 59.8 months; no metastasis or gastric cancer-related death occurred. The cumulative incidence of local recurrence 5 years after ESD was 11.9 %. All locally recurrent cancers were mucosal differentiated-type adenocarcinomas. Multivariate analysis indicated that a cancer-positive lateral margin length of ≥ 6 mm was significantly associated with local recurrence (hazard ratio 20.8; 95 % confidence interval 5.2 % - 82.9 %; P < 0.001). The cut-off value of 6 mm was determined by the receiver operating characteristic curve; the sensitivity and specificity for 5-year risk of developing local recurrence were 66.7 % and 95.6 %, respectively., Conclusions: A cancer-positive lateral margin length of ≥ 6 mm was an independent risk factor for local recurrence, and this may be a useful criterion for selecting high-risk cases for stricter management., (© Georg Thieme Verlag KG Stuttgart · New York.)

Colorectal villous adenoma is thought to be associated with a high risk of progression to adenocarcinoma. To better characterize the genetic alterations involved in colorectal carcinogenesis related to villous adenoma, we analyzed mutations in APC, BRAF, KRAS, TP53, and GNAS in 12 colorectal adenocarcinomas associated with villous adenomas. APC, KRAS, and BRAF mutations were identified in five, 11, and one lesion, respectively, and most of these mutations were shared between the villous adenoma and the adenocarcinoma components in the respective lesions, except in one lesion with APC mutations and in two lesions with KRAS mutations. TP53 mutations were observed exclusively in four adenocarcinoma components, consistent with their role in the progression from adenoma to adenocarcinoma. Activating GNAS mutations were found in nine villous adenomas; however, unexpectedly, these mutations were shared only in three associated adenocarcinomas. Notably, all six adenocarcinomas with discordant GNAS mutation statuses were nonmucinous type, whereas all the other adenocarcinomas, including three adenocarcinomas associated with GNAS wild-type villous adenomas, were mucinous type. The current study suggests that GNAS-mutated villous adenomas may not necessarily be direct precursors of associated adenocarcinomas. At the same time, our observations support the role of activating GNAS mutations in increased mucin production in colorectal neoplasms., (Copyright © 2014 Wiley Periodicals, Inc.)

Objectives: To evaluate the HER2 status in patients with Siewert type II esophagogastric junction carcinoma., Background: Trastuzumab is now approved for use in the treatment of human epidermal growth factor receptor 2 (HER2)-positive unresectable metastatic gastric or esophagogastric junction (EGJ) carcinoma. Several studies have evaluated HER2 status in EGJ carcinoma, but none has addressed the implication of HER2 positivity in patients with Siewert type II EGJ carcinoma., Methods: We retrospectively evaluated the frequency of HER2 positivity in a large single-center cohort of 208 patients with Siewert type II tumors. The relations between HER2 expression and the outcomes and other clinicopathologic features were examined., Results: Overall, 18.2 % (38/208) of patients in our cohort had HER2-positive tumors. HER2 positivity was associated only with differentiated carcinomas. The 5-year overall survival (OS) rate was 58.7 %. The 5-year OS rates in the patient groups with HER2-negative and HER2-positive tumors were 61.2 and 48.5 %, respectively. There was no significant difference between the groups. Recurrence in the liver was observed in 23.7 % patients of the HER2-positive group and 7.6 % patients of the HER2-negative group. Multivariate analysis to identify the risk factors for liver recurrence revealed only HER2 positivity (p = 0.0155) as an independent predictive factor., Conclusions: HER2 positivity is a powerful predictor of liver recurrence in patients with Siewert type II EGJ carcinoma. Use of trastuzumab in combination with chemotherapy in an adjuvant setting can be a potentially useful therapeutic strategy to prevent hepatic recurrence in patients with resectable EGJ adenocarcinoma showing HER2 overexpression.

Background: Recently, driver tyrosine kinase gene mutations have been detected in malignant tumors, including lung tumors. Notwithstanding their attractiveness as targets for molecular therapy, limited information is available regarding BRAF-mutated lung carcinomas., Materials and Methods: BRAF mutation status was determined in 2001 surgically resected nonsmall-cell lung cancer (NSCLC) cases using high-resolution melting analysis (HRMA) followed by Sanger sequencing and/or deep sequencing using next generation sequencer., Results: BRAF mutations were detected in 26 (1.3%) of 2001 NSCLC cases (25 adenocarcinomas and 1 squamous cell carcinoma). In the 26 cases, 13 mutation genotypes were identified, including V600E (8 of 26; 30.8%), G469A (6 of 26; 23.1%), K601E (4 of 26; 15.4%), and other residual mutations (1 of 26; 0.04%). Of the 13 genotypes, 4 genotypes (G464E, G596R, A598T, and G606R) had not been previously reported in lung cancer. The overall survival rate was not significantly different between patients with wild-type BRAF and those with V600E or non-V600E BRAF mutations (P = 0.49 and P = 0.15, respectively). Histomorphological analysis revealed that focal clear cell changes were present in 75% of V600E-mutated tumors. All V600E BRAF-mutated tumors were negative for other driver gene alterations including epidermal growth factor receptor (EGFR) and KRAS mutations and the anaplastic lymphoma kinase gene translocation, whereas five tumors with non-V600E BRAF mutations (four G469A and one G464E/G466R) showed concomitant EGFR mutations., Conclusion: The frequency of BRAF mutations in lung cancer was low in an Asian cohort. Furthermore, BRAF mutation status lacked prognostic significance in this patient population.

Background and Study Aim: Endoscopic resection has been favored for the management of intramucosal adenocarcinoma of the esophagogastric junction (AEGJ) over standard treatment with surgical resection. Several previous studies have reported only short-term outcomes. The aim of the present study was to report the long-term follow-up and outcomes of endoscopic submucosal dissection (ESD), a representative endoscopic resection method, for the management of superficial AEGJ., Patients and Methods: A retrospective cohort study included 53 consecutive patients with superficial AEGJ who underwent ESD between 2001 and 2007 at the National Cancer Center Hospital, Tokyo, Japan. Rates of overall survival, recurrence-free survival, and cause-specific survival of patients with AEGJ after endoscopic resection were analyzed., Results: The 5-year overall, recurrence-free, and cause-specific survival rates in the 53 patients were 94.2%, 92.3% and 96.1%, respectively. The median follow-up was 6.1 years. En bloc, R0, and curative resection rates were 100 %, 79 %, 68 %, respectively. In 36 patients with curative resection, the cause-specific survival rate was 100 % and no recurrence or metastases were detected. In 17 patients with non-curative resection, recurrence was found in three patients (17 %); two of the three patients died of their disease whilst one patient received chemotherapy., Conclusions: Superficial AEGJ can be well controlled by ESD when curative resection is achieved., (© Georg Thieme Verlag KG Stuttgart · New York.)

We previously reported a relationship between depth of submucosal invasion of early colorectal carcinomas and desmoplastic reaction (DR). However, poor inter-observer agreement on the histopathological diagnosis of DR in biopsy specimens with hematoxylin and eosin (H&E) staining has been the major critique of this tool. In this study, reproducibility of the histopathological diagnosis of DR was evaluated. Furthermore, we investigated the possible improvement of the reproducibility after education about histological characteristics and tried to identify histological characteristics that are most important in the recognition of DR. A total of 34 H&E stained slides were included in this study and analyzed by three pathologists. Slides were reviewed before and after education about histological characteristics of DR. Kappa statistics were used to compare the inter-observer variability. We investigated the relationship between DR and histopathological factor. The inter-observer agreement during the first session varied between 0.30 and 0.63, which improved during the second session toward an agreement between 0.58 and 0.71. Myofibroblast proliferation associated with cancer invasion was found to be the most useful in the diagnosis of DR. In conclusion, the correct detection of myofibroblasts may facilitate the standardization of diagnosis of DR., (© 2013 The Authors. Pathology International © 2013 Japanese Society of Pathology and Wiley Publishing Asia Pty Ltd.)

Background: There have been sporadic reports about synchronous as well as metachronous gastric adenocarcinoma and primary gastric lymphoma. Many reports have dealt with metachronous gastric adenocarcinoma in mucosa-associated lymphoid tissue lymphoma of stomach. But to our knowledge, there have been no reports that document the increased incidence of metachronous gastric adenocarcinoma in patients with gastric diffuse large B-cell lymphoma. This retrospective study was conducted to estimate the incidence of metachronous gastric adenocarcinoma after primary gastric lymphoma treatment, especially in diffuse large B-cell lymphoma., Methods: The retrospective cohort study of 139 primary gastric lymphoma patients treated with radiotherapy at our hospital. Mean observation period was 61.5 months (range: 3.7-124.6 months). Patients profile, characteristics of primary gastric lymphoma and metachronous gastric adenocarcinoma were retrieved from medical records. The risk of metachronous gastric adenocarcinoma was compared with the risk of gastric adenocarcinoma in Japanese population., Results: There were 10 (7.2%) metachronous gastric adenocarcinoma patients after treatment of primary gastric lymphomas. It was quite high risk compared with the risk of gastric carcinoma in Japanese population of 54.7/100,000. Seven patients of 10 were diffuse large B-cell lymphoma and other 3 patients were mixed type of diffuse large B-cell lymphoma and mucosa associated lymphoid tissue lymphoma. Four patients of 10 metachronous gastric adenocarcinomas were signet-ring cell carcinoma and two patients died of gastric adenocarcinoma. Metachronous gastric adenocarcinoma may have a more malignant potential than sporadic gastric adenocarcinoma. Old age, Helicobacter pylori infection and gastric mucosal change of chronic gastritis and intestinal metaplasia were possible risk factors for metachronous gastric adenocarcinoma., Conclusion: There was an increased risk of gastric adenocarcinoma after treatment of primary gastric lymphoma, especially of diffuse large B-cell lymphoma.

Background and Study Aim: Close observation after noncurative endoscopic resection for early gastric cancer (EGC) is an acceptable option if a positive horizontal margin or piecemeal resection of differentiated-type adenocarcinoma is the only noncurative factor. When locally recurrent EGC is subsequently detected, endoscopic submucosal dissection (ESD) may be performed, although only limited research has been reported regarding the outcomes. We aimed to evaluate the effectiveness, safety, and long-term clinical outcomes of ESD performed for locally recurrent EGC., Patients and Methods: Endoscopic resection was performed in 3704 patients with a total of 4216 EGC lesions between January 1997 and December 2011 at our institution. During this period, 95 patients with 95 locally recurrent EGCs following their endoscopic resection underwent ESD performed by experts, which we retrospectively reviewed. The prior endoscopic resection procedures were endoscopic mucosal resection in 75 cases and ESD in 20., Results: Of the 95 cases, en bloc resection was achieved in 90.5 %, R0 resection in 84.2 %, and curative resection in 81.1 %. Median procedure time was 70 minutes; no bleeding requiring blood transfusion was seen. There were six perforations (6.3 %), with one necessitating emergency surgery. Within a median follow-up period of 76.4 months (range, 10.5 - 170.0 months), second local recurrences occurred in three patients. Five-year overall and disease-specific survival rates were 92.8 % and 100 %, respectively., Conclusions: ESD was safe and effective with favorable long-term clinical outcomes for locally recurrent EGC following endoscopic resection., (© Georg Thieme Verlag KG Stuttgart · New York.)

Background and Study Aims: Intramucosal undifferentiated early gastric cancer (EGC) up to 2 cm in size without ulceration has been treated by endoscopic submucosal dissection (ESD) because the incidence of lymph node metastasis is negligible. The aim of this retrospective study was to clarify the short-term and long-term outcomes of ESD carried out to treat undifferentiated EGC., Patients and Methods: Between January 1999 and September 2011, 113 patients with poorly differentiated adenocarcinoma or signet ring cell carcinoma on preoperative biopsy underwent ESD. In 16 patients differentiated EGC had been diagnosed after the ESD and these patients were excluded from the study. Short-term outcomes were evaluated in the remaining 97 patients with undifferentiated EGC, and long-term outcomes analyzed in the 79 patients with undifferentiated EGC who had undergone ESD between 1999 and 2008., Results: En bloc and R0 resection were achieved in 99.0 % and 90.7 % of patients, respectively. Median procedure time was 45 minutes. Postoperative bleeding, perforation during the procedure, and delayed perforation were noted in 4.1 %, 3.1 %, and 1.0 % respectively. Curative resection was achieved in 63.9 %. Additional surgery was performed in 21 of 35 patients in whom resection was noncurative: one (4.8 %) had local residual tumor and two (9.5 %) had lymph node metastases. Of the 46 /79 patients in the long-term outcome group who had curative resection, none had local recurrence or lymph node or distant metastasis during a median follow-up of 76.4 months. The 5-year overall mortality rate after curative resection was 7.0 %, and no patient died of gastric cancer., Conclusions: ESD for undifferentiated EGC can achieve curative resection with an excellent 5-year mortality rate., (© Georg Thieme Verlag KG Stuttgart · New York.)

A 67-year-old male underwent endoscopic submucosal dissection (ESD) to treat early gastric cancer (EGC) in 2001. The lesion (50 mm × 25 mm diameter) was histologically diagnosed as poorly differentiated adenocarcinoma, with an ulcer finding. Although the tumor was confined to the mucosa with no evidence of lymphovascular involvement, the ESD was regarded as a non-curative resection due to the histological type, tumor size, and existence of an ulcer finding (as indicated by the 2010 Japanese gastric cancer treatment guidelines, ver. 3). Despite strong recommendation for subsequent gastrectomy, the patient refused surgery. An alternative follow-up routine was designed, which included five years of biannual clinical examinations to detect and measure serum tumor markers and perform visual assessment of recurrence by endoscopy and computed tomography scan after which the examinations were performed annually. The patient's condition remained stable for eight years, until a complaint of back pain in 2010 prompted further clinical investigation. Bone scintigraphy indicated increased uptake. Histological examination of biopsy specimens taken from the lumbar spine revealed adenocarcinoma resembling the carcinoma cells from the EGC that had been treated previously by ESD, and which was consistent with immunohistochemical findings of gastrointestinal tract cancer. Thus, the diagnosis of bone metastasis from EGC was made. The reported rates of EGC recurrence in surgically resected cases range 1.4%-3.4%, but among these bone metastasis is very rare. To our knowledge, this is the first reported case of bone metastasis from EGC following a non-curative ESD and occurring after an eight-year disease-free interval.

Neuroendocrine carcinoma (NEC) of the stomach has been recognized as a highly malignant tumor; however, because of its rarity, limited information is available regarding its clinicopathologic characteristics. Here, we investigated the morphologic and immunohistochemical features and prognosis of 51 cases of gastric NEC. Histologically, 40 lesions were large cell type, and 11 were small cell type. The large majority of the tumors exhibited a solid growth pattern (94%), with subsets of tumors showing trabecular (18%), scirrhous (10%), or tubular growth patterns (6%). Thirty-six cases (71%) had adenocarcinoma components and/or dysplasia. Among them, 26 cases (51%) were associated with intramucosal adenocarcinoma or dysplasia. Immunohistochemically, synaptophysin, chromogranin A, and CD56 were diffusely expressed in 48 (94%), 44 (86%), and 24 cases (47%), respectively. Two recently reported neuroendocrine markers, ASH1 and NKX2.2, were diffusely positive in 12 (24%) and 17 cases (33%), respectively. The diffuse or focal expression of TTF-1 was observed in 19 cases (37%). Among the 41 patients who underwent a curative resection, 16 patients (39%) developed radiologic recurrences, and the liver was the most frequent site of recurrence (11 patients, 27%). The 3- and 5-year overall survival rates were 57.8% and 44.7%, respectively. Regarding patient outcome, none of the histologic subclassifications, including small cell versus large cell types and the presence versus the absence of adenocarcinoma components and/or dysplasia, were significant. In a multivariate analysis, curative surgery was identified as the sole independent prognostic factor (P=0.03). Although gastric NECs exhibit significant morphologic diversity, their histologic subclassification is unlikely to be of immediate clinical relevance.

Background: Lymphatic and venous involvement is a critical factor in the curability assessment of endoscopically resected gastric cancers; however, the risk factors for lymphatic and venous involvement in endoscopically resected gastric cancers remain unknown., Methods: To identify risk factors for lymphatic and venous involvement in endoscopically resected gastric cancers, we retrospectively reviewed a consecutive series of 1229 endoscopically resected gastric cancers in 1083 patients treated between January 2009 and December 2011., Results: Lymphatic and venous involvement was detected in 57 (4.6%) and 32 (2.6%) lesions, respectively. A multivariate analysis identified a larger tumor size, deeper invasion (submucosal invasion or deeper), and the presence of a papillary or an undifferentiated-type adenocarcinoma component as independent risk factors for lymphatic involvement. As for venous involvement, deeper invasion (≥500 μm submucosal invasion), a macroscopically elevated type, and the presence of an undifferentiated-type adenocarcinoma component were identified as independent risk factors., Conclusions: The present study identified the independent risk factors for lymphatic and venous involvement in endoscopically resected gastric cancers. The recognition of these risk factors would help in the selection of lesions that may require a particularly careful histological evaluation.

Gastric adenocarcinoma of the fundic gland type (GAFG) and pyloric gland adenoma (PGA) have recently been recognized as rare types of neoplasia. We performed comparative immunohistochemical and genetic analyses of 3 GAFGs and 12 PGAs. All of the 3 GAFGs were diffusely positive for pepsinogen-I, MIST1 and MUC6, indicating the predominantly chief cell/mucous neck cell differentiation of these tumors. A small number of H.K-ATPase-positive parietal cells were also scattered. PGAs invariably exhibited diffuse MUC6 and TFF2 expression, consistent with the pyloric gland differentiation of these tumors. Ten of the 12 PGAs also unexpectedly exhibited focal expression of pepsinogen-I and MIST1, suggesting that PGAs often show focal chief cell differentiation and phenotypically resemble mucous neck cells rather than pyloric glands. The mutation analyses revealed activating GNAS mutations, which have been reported to be frequently detected in PGAs, in two of the GAFGs. While GAFGs and PGAs are morphologically distinct lesions, our observations showed their partially overlapping immunohistochemical profiles and shared presence of GNAS mutations, in addition to their common occurrence in the fundic gland mucosa. Based on these observations, we suggest that both GAFGs and PGAs are closely related lesions characterized by a mucous neck cell/chief cell lineage phenotype., (© 2013 The Authors. Pathology International © 2013 Japanese Society of Pathology and Wiley Publishing Asia Pty Ltd.)

Determination of the risk of lymph-node metastasis is crucial in making appropriate surgical or endoscopic resection therapeutic decisions. The actual number of patients with esophageal adenocarcinomas and esophagogastric junction adenocarcinomas remains relatively low in Japan; therefore, debate still exists as to whether or not intramucosal esophageal adenocarcinoma has a risk of lymph-node metastasis. We report herein a case of lymph-node metastasis in a surgical resection of an esophageal adenocarcinoma with muscularis mucosae invasion, but no lymphovascular involvement., (© 2013 The Authors. Digestive Endoscopy © 2013 Japan Gastroenterological Endoscopy Society.)

Local recurrence after endoscopic piecemeal mucosal resection (EPMR) for colorectal tumors is a crucial issue. However, such recurrence is usually detected within one year and cured with additional endoscopic treatment, which makes EPMR acceptable. Herein, we report a rare case of repeatedly recurrent colon cancer involving the appendiceal orifice after EPMR, which was not cured with additional endoscopic treatments. A 67-year-old man was referred to us for endoscopic treatment of a 25 mm cecal tumor spreading to the appendiceal orifice in May 2002. The tumor was resected with EPMR, showing well differentiated intramucosal adenocarcinoma with a positive lateral cut margin of tubular adenoma. Endoscopic surveillance was conducted and the first local recurrence was detected in August 2006. Although we resected it endoscopically, the second local recurrence was found in September 2007 and we removed it with endoscopic resection again. However, the third local recurrence was detected in March 2008. Although endoscopic resection was performed also for the third recurrence, curative resection was not achieved. In February 2009, laparoscopic assisted colectomy was performed and histopathological examination showed well differentiated adenocarcinoma with deep submucosal invasion. This case is important in considering indication for endoscopic resection in colorectal tumors involving the appendiceal orifice.

Gastric and duodenal adenomas exhibit a significant morphological and phenotypical diversity and are classified into intestinal-type, foveolar-type and pyloric gland adenomas. We analysed the mutations in GNAS, KRAS, BRAF and CTNNB1 and the expressions of mismatch repair (MMR) proteins in 80 gastric and 32 duodenal adenomas with histologically distinct subtypes, as well as in 71 gastric adenocarcinomas. Activating GNAS mutations were found in 22 of the 35 pyloric gland adenomas (PGAs; 63%) but in none of the foveolar-type or intestinal-type adenomas or the adenocarcinomas. Fourteen PGAs (41%), two foveolar-type adenomas (9%), five intestinal-type adenomas (9%) and one adenocarcinoma (1%) had KRAS mutations. BRAF mutations were absent in all the adenomas and adenocarcinomas that were examined. CTNNB1 mutations were only found in two intestinal-type adenomas (4%). Notably, 13 of the 14 KRAS-mutated gastric and duodenal PGAs had concurrent GNAS mutations. The loss of the MMR proteins, which is indicative of microsatellite instability, was observed in one PGA (3%), 12 foveolar-type adenomas (52%), one intestinal-type adenoma (2%) and five adenocarcinomas (7%). These observations indicate that each histological subtype of gastric and duodenal adenomas has a distinct genetic background. In particular, the present study identified the frequent presence of activating GNAS mutations, which are often associated with KRAS mutations, as a characteristic genetic feature of PGAs of the stomach and duodenum., (Copyright © 2012 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.)

Whereas attention in the past has been focused on goblet cells as the primary marker for Barrett's esophagus (BE), the recent change in the definition now includes the non-goblet cell columnar cell-lined esophagus. In the present study the histological features of neoplasia of the lower esophagus and esophago-gastric junction in a German cohort were examined using immunohistochemical staining for MUC, CD10, intestinal and gastric type major tight junction proteins (claudins). Experimental studies using rat duodenogastric content reflux models have also been performed and data show that most neoplastic lesions of the esophageal glands in humans express gastric mucin phenotypes. Cardiac type mucosa was the main histological type in the surrounding mucosa of neoplastic lesions; however, most cardiac type mucosa has intestinal type tight junction proteins. BE with goblet cells has been reported to originate from stem cells located in the basal layer of esophageal squamous cell epithelium in previous models. However, the cardiac type mucosa seems to develop from the site of the stomach and not from the basal layer of esophageal squamous cell epithelium according to our model.

Gastric cancer is one of the most common malignancies worldwide and patients with advanced gastric cancer still have poor clinical outcomes. The overexpression of leucine-rich repeat-containing G protein-coupled receptor 5 (LGR5) mRNA in colorectal cancer and its correlation with clinicopathological factors were recently reported by us. In this study, we show LGR5 mRNA overexpression in human gastric cancer specimens by quantitative RT-PCR and in situ hybridization and assess a correlation with clinicopathological factors. The mean expression of LGR5 mRNA in cancerous tissues was five times higher than that in normal tissue (P = 0.0002). Furthermore, LGR5 mRNA expression show marked variation among cases and significantly increased in cases where lymphatic invasion was present compared with those where it was absent (P = 0.0056). Although the mean expression level of LGR5 was observed to be higher in nodal metastasis and venous invasion positive cases compared to negative cases, a significant difference was not observed. These results suggest that LGR5 can be a biomarker for malignancy in gastric cancer., (© 2012 The Authors. Pathology International © 2012 Japanese Society of Pathology and Wiley Publishing Asia Pty Ltd.)

Extremely well-differentiated tubular adenocarcinomas (EWDAs) of the stomach are characterized by surface maturation and their mimicking of intestinal metaplasia. Endoscopically, intramucosal EWDAs are frequently ill defined with indistinct borders due to the pallor of the neoplastic mucosa and the lack of contrast against the background atrophic and metaplastic mucosa. We evaluated the effectiveness of endoscopic resection for EWDAs after endoscopic submucosal dissection (ESD). Among 872 patients with early gastric cancer, 17 EWDAs were identified (1.9 %). Endoscopically, the flat or depressed type was significantly more common among EWDAs (88.2 %) than among early gastric cancers of other histologies (37.8 %; P < 0.01). The discrepancy between endoscopically estimated tumor size and tumor size as confirmed in pathology reports was significantly greater among EWDAs (18.4 ± 22.0  mm) than among others (5.8 ± 7.5  mm). Involvement of the lateral resection margin was more common (29.4 % vs. 2.5 %; P < 0.05), and complete resection was achieved less often in EWDAs (47.1 % vs. 80.4 %; P = 0.01) compared to the others. EWDAs are associated with higher rates of incomplete resection after ESD, especially along the lateral margins. Pathologists should alert endoscopists when this diagnosis is made, with its associated risks; and endoscopists should pay particular attention to the extent of these tumors during resection., (© Georg Thieme Verlag KG Stuttgart · New York.)

Novel candidates of biomarker and therapeutic target in colorectal cancer (CRC) were investigated using a proteomic approach. The proteome of normal colorectal epithelial tissues was compared with that of the tumor ones in 59 CRC patients using two-dimensional difference gel electrophoresis. Of 3458 protein spots, 110 exhibited statistically significant (p<0.01) differences in intensity (more than 2.5-folds) between the normal and tumor tissue groups. Of 67 unique gene products that were identified for 105 of the 110 protein spots, we focused on the higher expression of the adenoma polyposis coli-binding protein EB1 (EB1). EB1 was originally discovered as a binding protein of APC, which is a tumor suppressor gene product, and the expression of EB1 has been associated with poor prognosis in several malignancies but not in CRC. Immunohistochemical analysis of the 132 CRC cases revealed that EB1 was overexpressed in tumor cells in correlation with poor prognosis. Suppression of EB1 by RNAi inhibited CRC cell proliferation and invasion. In this study, the overexpression of EB1 in CRC tissues correlating with prognosis, and its functional contribution to the malignant phenotypes of CRC cells are described. The present findings indicate that EB1 is a potential biomarker and therapeutic target in CRC., (Copyright © 2012 Elsevier B.V. All rights reserved.)

Currently in Japan, differentiated gastric submucosal invasive cancers <500 μm (SM1) with negative lymphovascular involvement are included in expanded pathological criteria for curative endoscopic treatment. This is based on a retrospective examination of surgical resection cases in which patients suitable for such expanded criteria were determined to have a negligible risk of lymph node metastasis. We performed endoscopic submucosal dissection on a 65-year-old male with early gastric cancer in April 2005, and pathology revealed a well-differentiated adenocarcinoma, 21 × 10 mm in size, SM1 invasion depth and negative lymphovascular invasion as well as tumor-free margins, so the case was diagnosed as a curative resection. This case, however, resulted in lymph node metastasis that was diagnosed by endoscopic ultrasonography with fine-needle aspiration biopsy in May 2009. Distal gastrectomy with D2 lymph node dissection was then performed, confirming lymph node metastasis from the original gastric cancer.

Background: Dome-type carcinoma (DC) is a distinct variant of colorectal adenocarcinoma and less than 10 cases have been described in the literature. Most of the previously reported cases were early lesions and no endoscopic observations have been described so far. We herein report a case of a DC invading the subserosal layer, including endoscopic findings., Case Presentation: A highly elevated lesion in the transverse colon was diagnosed by colonoscopy in a 77-year-old man. The tumor appeared to be similar to a submucosal tumor (SMT), however, a demarcated area of reddish and irregular mucosa was observed at the top of the tumor. There were no erosions or ulcers. Laparoscopic-assisted right hemicolectomy was performed and pathological examination revealed a well-circumscribed tumor invading the subserosal layer. The tumor was a well-differentiated adenocarcinoma associated with a dense lymphocytic infiltration and showed expansive growth. The overlying mucosal layer showed high-grade dysplasia., Conclusion: The present lesion was diagnosed as a DC of the colon invading the subserosal layer. Because the association of mucosal dysplasia is common in DCs, the detection of dysplastic epithelium would be important to discriminate DCs from SMTs., (© 2012 Yamada et al; licensee BioMed Central Ltd.)

Background and Aim: As the histogenesis and development of α-fetoprotein-producing gastric cancer (AFPGC) have not yet been elucidated, we analyzed the histologic and immunologic relationship between the histologic type of the mucosal lesion considered to be the primary lesion, and that of its invasive lesion, in 36 cases of AFPGC., Patients and Methods: We reviewed 23 AFPGCs with mucosal lesions (1 mucosal and 22 submucosal or deeper invasive tumors) among 36 AFPGCs that had been resected endoscopically or surgically between 1970 and 2005. AFPGC was defined as a tumor showing immunohistochemical positivity for either α-fetoprotein (AFP) or glypican-3. Histologic types were divided into hepatoid (HPT), enteroblastic (ENT), yolk sac tumor, and common (COM) adenocarcinoma type. The tumor phenotypes were classified into gastric, gastrointestinal, and intestinal types on the basis of immunohistochemical analysis., Results: Among the histologic types of mucosal lesions, the COM and ENT mixed type was observed in 65.2% of cases (15/23 patients), COM alone in 26.1% (6/23), and ENT alone in 8.7% (2/23) of cases. Among the invasive lesions, 16 cases (72.7%) were HPT. Both AFP and glypican-3 were positive in 60.9% (14/23) of mucosal lesions and in 90.9% (20/22) of invasive lesions. With regard to phenotypic expression, 82.6% (19/23) of mucosal lesions were the intestinal type, compared with 95.5% (21/22) of invasive lesions., Conclusions: These findings suggest that many cases of AFPGC develop as COM or ENT in the mucosa, which differentiate into ENT and HPT during the process of tumor invasion and proliferation, acquiring AFP production ability.

Breast carcinomas sometimes metastasize to the stomach, and the histopathologic distinction of such metastases from primary gastric adenocarcinomas is often difficult. We characterized the clinicopathologic features of 21 breast carcinomas that had metastasized to the stomach and examined the use of a panel of antibodies, including hepatocyte nuclear factor 4A, for distinguishing the metastases from primary gastric diffuse-type adenocarcinomas. Histologically, all the metastatic breast carcinomas showed a poorly differentiated and/or signet ring cell morphology. Although most metastatic breast and primary gastric carcinomas contained signet ring cell components, the cases that were predominantly or exclusively composed of univacuolated-type signet ring cells were limited to metastatic breast carcinomas. Immunohistochemically, hepatocyte nuclear factor 4A was expressed in all 33 primary gastric carcinomas that were examined but was never expressed in metastatic breast carcinomas. Previously reported markers for breast and gastric carcinomas also showed a high specificity, but their sensitivities were quite variable. Estrogen receptor α, progesterone receptor, mammaglobin, and gross cystic disease fluid protein 15 were expressed in 76%, 33%, 52%, and 62%, respectively, of the metastatic breast carcinomas, whereas none of the primary gastric carcinomas expressed these antigens. CDX2, MUC5AC, MUC6, and CK20 were expressed in 36%, 85%, 27%, and 55%, respectively, of the primary gastric carcinomas. All the metastatic breast carcinomas were negative for these antibodies except for 1 case that expressed MUC5AC. Overall, the use of immunohistochemistry efficiently discriminated metastatic breast carcinomas from primary gastric carcinomas. In particular, the present study identified hepatocyte nuclear factor 4A as an excellent marker for differentiating the 2 lesions.

Purpose: To clarify the prognostic impact of tumor nodules without residual lymph node (LN) structure (ND) in colorectal cancer and to determine optimal categorization of ND in tumor staging., Patients and Methods: A multicenter, retrospective pathologic review was performed for 1716 patients with stages I to III curatively resected colorectal cancer treated at 11 institutions between 1994 and 1998. An additional 2242 patients from nine institutions were enrolled between 1999 and 2003 as a second cohort to validate the results., Results: LN metastasis (LNM) and ND were observed in 33.7% and 16.0% (smooth-contour nodule [S-ND], 8.2%; irregular-contour nodule [I-ND], 10.7%) of patients in the first cohort. S-ND and I-ND were similarly distributed in the regional area. There was no considerable difference in the impact on survival between S-ND (hazard ratio [HR], 2.7; 95% CI, 1.9 to 3.8) and I-ND (HR, 4.3; 95% CI, 3.3 to 5.8) or between LNM (HR, 4.5; 95% CI, 3.4 to 6.0) and ND (HR, 4.0; 95% CI, 3.1 to 5.3). LNM and ND were similarly associated with the mode of recurrence. Tumor nodules ≥ 5 mm growing with venous/perineural invasion (ND [v/pni+]), judged with 0.61 κ value among 11 observers, had an independent prognostic value for 5-year survival of 42%; similar results were observed in the second cohort., Conclusion: These results do not support the TNM system in which S-ND is treated differently from I-ND in tumor staging; LNM and ND should be considered together in the same category. The presence of ND (v/pni+) has a considerable adverse prognostic effect.

Background: Recently, especially in Japan, several researchers have suggested that colorectal cancer can develop not only through an adenoma-carcinoma sequence but also from normal mucosa via a de novo pathway, and that these de novo cancers have more aggressive malignant potential. We report a case of aggressive colon cancer resulting in systemic metastasis despite small tumour size., Case Presentation: A 35-year-old woman presented at the referring hospital with swelling of the left cervical lymph node. Biopsy of the lymph node revealed metastatic adenocarcinoma; however, CT scan and mammography were unable to identify the site of the primary lesion. She was diagnosed with unknown primary cancer and referred to our hospital for further examination. Immunohistochemical reevaluation showed the cervical lymph node biopsy specimen to be positive for CDX2 and CK20 and negative for CK7 expression, leading us to suspect the presence of a primary colorectal cancer. We performed a total colonoscopy, and detected a small protruding lesion in the transverse colon. The tumour was only 12 mm in diameter, with a central depressed component and a severely thickened stalk, which suggested direct cancer invasion of the deep submucosa. We concluded that this lesion was the site of origin of the metastasis despite the small tumour size, and performed diagnostic endoscopic mucosal resection. The lesion was found to have an intramucosal cancer component, demonstrating that this lesion represented primary colon cancer. The patient was referred to the gastrointestinal oncology division for systemic chemotherapy., Conclusions: In this case, immunohistochemical findings strongly suggested the existence of a colorectal cancer. The non-polypoid gross appearance of the tumour suggested that it can originate de novo , thus providing a valuable case in support of the aggressive malignant potential of a de novo colorectal cancer pathway.

The adenoma-adenocarcinoma sequence in the colon is generally accepted. Regarding the stomach, however, opinions about tumorigenesis are different. We analyzed the phenotypes, DNA ploidy patterns, and microsatellite regions linked to adenomatous polyposis coli (APC) gene on chromosome 5q of low-grade gastric adenomas/dysplasias, Vienna Category 3, to investigate whether these lesions have the potential to become adenocarcinomas. Phenotypes were determined by immunohistochemical staining with monoclonal antibodies MUC2, MUC5AC, MUC6, CD10, and Cdx2. DNA ploidy patterns were determined by static cytofluorometry. Microsatellite analyses were performed using Genescan on genetic analyzer ABI PRISM 310. None of the 15 cases showed coexisting high-grade adenomas/dysplasias or adenocarcinoma. Eighty percent of the cases had the complete intestinal phenotype, and the remainder showed slight MUC6 positivity for the intestinal phenotype. All cases were positive for Cdx2 and showed diploid DNA. In addition, 46.7% of the cases exhibited loss of heterozygosity (LOH) of chromosome 5q. Except for one case, 5q-LOH was detected at a single locus in cases with the complete intestinal phenotype. According to previous studies, most gastric adenocarcinomas have the gastric phenotype and no 5q-LOH. These results suggest that low-grade gastric adenomas/dysplasias, Vienna category 3, seldom progress to gastric adenocarcinomas of the differentiated type.

The drs gene was originally isolated as a suppressor of v-src transformation. Expression of drs mRNA is markedly downregulated in a variety of human cancer cell lines and tissues, suggesting the potential role of this gene as a tumor suppressor. Previously, we found that Drs protein associates with ASY/Nogo-B/RTN-x(S), an apoptosis-inducing protein in the endoplasmic reticulum, and sequentially activates caspases to induce apoptosis in human cancer cells without involvement of the mitochondria. In this study, we investigated the tumor suppressor function of drs and the correlation between Drs-mediated apoptosis and tumor suppression by generating a gene-knockout (KO) mouse. Between 7 and 12 months after birth, malignant tumors including lymphomas, lung adenocarcinomas and hepatomas were generated in about 30% of the drs KO mice, whereas no tumors were found in any of the wild-type mice during the same period of time. drs KO embryonic fibroblasts also showed enhanced sensitivity to transformation by v-src oncogene. Reintroduction of drs into a tumor cell line derived from the tumor of a drs KO mouse led to the suppression of tumor formation in nude mice, which was accompanied by enhanced apoptosis and the activation of caspase-9 and -3. Furthermore, introduction of drs into this cell line enhanced sensitivity to apoptosis mediated by caspase-3, -9 and -12 under low serum culture conditions. The present results thus indicate that drs contributes to the suppression of malignant tumor formation, and this suppression is closely correlated with drs-mediated apoptosis.