Identification of a high-risk subtype of intestinal-type Japanese gastric cancer by quantitative measurement of the luminal tumor proportion

Background: We hypothesized that the relative proportion of tumor (PoT) at the luminal surface can predict gastric cancer (GC) patient survival. Methods: We measured the luminal PoT in resection specimens from 231 GC patients with stage II/III disease who had surgery at the Kanagawa Cancer Center, Yokohama, Japan. Tissue microarrays were used to assess the extent of immune cell infiltration by CD45 immunohistochemistry. Results were related to histopathological features and patient overall survival (OS). Results: PoT was significantly lower in diffuse‐type (30%) compared to intestinal‐type GC (41%), P = 0.03. Patients with low PoT intestinal‐type GC survived significantly longer than patients with high PoT intestinal‐type GC (5 years OS: 78% vs 47%, P = 0.0112). Low PoT was an independent favorable prognostic factor in multivariate analysis in intestinal‐type GC. Low PoT was correlated with high content of CD45‐positive immune cells (P = 0.035). There was no relationship between PoT and survival in diffuse‐type GC. Conclusions: This is the first study to identify a subgroup of patients with stage II/III intestinal‐type GC at high risk of recurrence by measuring PoT at the luminal surface. The relationship between PoT and immune cell content provides an initial insight into potential underlying biological mechanisms

Microsatellite Instability Is Associated with the Clinicopathologic Features of Gastric Cancer in Sporadic Gastric Cancer Patients

Purpose: Replication error is an important mechanism in carcinogenesis. The microsatellite instability (MSI-H) of colorectal cancers is associated with the development of multiple cancers. The influence of MSI-H on the development of multiple gastric cancers in sporadic gastric cancer patients has not been defined. This study was performed to reveal the association between the clinicopathologic features and MSI in sporadic gastric cancers. Materials and Methods: Between July 2004 and March 2009, the clinicopathologic characteristics, including MSI status, were evaluated in 128 consecutive patients with sporadic gastric cancers. None of the patients had hereditary non-polyposis colorectal cancer of familial gastric cancer. The markers that were recommended by the NCI to determine the MSI status for colorectal cancers were used. Results: MSI-H cancers were found in 10.9% of the patients (14/128). Synchronous gastric cancers were shown in 4 patients (3.1%). Synchronous cancers were found in 2 of 14 patients with MSI-H gastric cancer (14.3%) and 2 of 114 patients with MSS gastric cancer (1.8%; P=0.059, Fisher's exact test). Among the patients with synchronous cancer 50% (2/4) had MSI-H cancer, but 9.7% of the patients (12/124) without synchronous cancer had MSI-H cancer. MSI-H (RR, 24.7; 95% CI, 1.5~398.9; P=0.024) was related with to synchronous gastric cancer, but age, gender, family history, histologic type, location, gross morphology, size, and stage were not related to synchronous gastric cancer. Conclusions: MSI is associated with the intestinal-type gastric cancer and the presence of multiple gastric cancers in patients with sporadic gastric cancer. Special attention to the presence of synchronous and the development of metachronous multiple cancer in patients with MSI-H gastric cancer is needed. ?? 2010 by The Korean Gastric Cancer Association