Person:

Huang, Qin

AIM: To investigate the clinicopathologic features which predict surgical overall survival in patients with proximal gastric carcinoma involving the esophagus (PGCE). METHODS: Electronic pathology database established in the Department of Pathology of the Nanjing Drum Tower Hospital was searched for consecutive resection cases of proximal gastric carcinoma over the period from May 2004 through July 2009. Each retrieved pathology report was reviewed and the cases with tumors crossing the gastroesophageal junction line were selected as PGCE. Each tumor was re-staged, following the guidelines on esophageal adenocarcinoma, according to the 7th edition of the American Joint Commission on Cancer Staging Manual. All histology slides were studied along with the pathology report for a retrospective analysis of 13 clinicopathologic features, i.e., age, gender, Helicobacter pylori (H. pylori) infection, surgical modality, Siewert type, tumor Bormann's type, size, differentiation, histology type, surgical margin, lymphovascular and perineural invasion, and pathologic stage in relation to survival after surgical resection. Prognostic factors for overall survival were assessed with uni- and multi-variate analyses. RESULTS: Patients' mean age was 65 years (range: 47-90 years). The male: female ratio was 3.3. The 1-, 3- and 5-year overall survival rates were 87%, 61% and 32%, respectively. By univariate analysis, age, male gender, H. pylori, tumor Bormann's type, size, histology type, surgical modality, positive surgical margin, lymphovascular invasion, and pT stage were not predictive for overall survival; in contrast, perineural invasion (P = 0.003), poor differentiation (P = 0.0003), > 15 total lymph nodes retrieved (P = 0.008), positive lymph nodes (P = 0.001), and distant metastasis (P = 0.005) predicted poor post-operative overall survival. Celiac axis nodal metastasis was associated with significantly worse overall survival (P = 0.007). By multivariate analysis, ≥ 16 positive nodes (P = 0.018), lymph node ratio > 0.2 (P = 0.003), and overall pathologic stage (P = 0.002) were independent predictors for poor overall survival after resection. CONCLUSION: Patients with PGCE showed worse overall survival in elderly, high nodal burden and advanced pathologic stage. This cancer may be more accurately staged as gastric, than esophageal, cancer.

Background: The genetics of advanced biliary tract cancers (BTC), which encompass intra- and extra-hepatic cholangiocarcinomas as well as gallbladder carcinomas, are heterogeneous and remain to be fully defined. Methods: To better characterize mutations in established known oncogenes and tumor suppressor genes we tested a mass spectrometric based platform to interrogate common cancer associated mutations across a panel of 77 formalin fixed paraffin embedded archived BTC cases. Results: Mutations among three genes, KRAS, NRAS and PIK3CA were confirmed in this cohort. Activating mutations in PIK3CA were identified exclusively in GBC (4/32, 12.5%). KRAS mutations were identified in 3 (13%) intra-hepatic cholangiocarcinomas and 1 (33%) perihillar cholangiocarcinoma but were not identified in gallbladder carcinomas and extra-hepatic cholangiocarcinoma. Conclusions: The presence of activating mutations in PIK3CA specifically in GBC has clinical implications in both the diagnosis of this cancer type, as well as the potential utility of targeted therapies such as PI3 kinase inhibitors.

Lgr5 has recently been identified as a murine marker of intestinal stem cells. Its expression has not been well characterized in human gastrointestinal tissues, but has been reported in certain cancers. With the increasing appreciation for the role of cancer stem cells or tumor-initiating cells in certain tumors, we sought to explore the expression of Lgr5 in normal and premalignant human gastrointestinal tissues. Using standard immunostaining, we compared expression of Lgr5 in normal colon and small intestine vs. small intestinal and colonic adenomas and Barrett's esophagus. In the normal tissue, Lgr5 was expressed in the expected stem cell niche, at the base of crypts, as seen in mice. However, in premalignant lesions, Lgr5+ cells were not restricted to the crypt base. Additionally, their overall numbers were increased. In colonic adenomas, Lgr5+ cells were commonly found clustered at the luminal surface and rarely at the crypt base. Finally, we compared immunostaining of Lgr5 with that of CD133, a previously characterized marker for tumor-initiating cells in colon cancer, and found that they identified distinct subpopulations of cells that were in close proximity, but did not costain. Our findings suggest that (1) Lgr5 is a potential marker of intestinal stem cells in humans and (2) loss of restriction to the stem cell niche is an early event in the premalignant transformation of stem cells and may play a role in carcinogenesis.