Phenotypic classification of well-differentiated gastric adenocarcinoma

Abstract

To investigate the genotypes of well-differentiated non-cardiac gastric adenocarcinoma and their clinicopathological significance. Sixty-four cases of well-differentiated non-cardiac gastric adenocarcinoma were included in this study. The expressions of intestinal phenotypic markers including CDX2, MUC2, Li-cadherin, CD10, Hepatocyte(Hep) and Villin, and gastric phenotypic markers including MUC5AC and pS2 were detected immunohistochemically. Based on the expressions of phenotypic markers, 64 cases can be divided into four phenotypes. Cases only expressing intestinal phenotypic markers were classified as intestinal phenotype; cases only expressing gastric phenotypic markers as gastric phenotype; cases expressing both intestinal and gastric phenotypic markers as gastrointestinal phenotype; and cases expressing neither intestinal nor gastric phenotypic marker as null phenotype. The association of phenotype and clinic-pathological parameters was analyzed. We also detected the expressions of markers related to the development and progression of cancer, including Rb, P53, c-Met, MIF, TGF-β-RII, β-catenin, CD44v6 and E-cadherin. Of 64 cases, 33(51.6%) were intestinal type, 3(4.7%) were gastric type, 25(39.1%) were gastrointestinal type and 3(4.7%) were null type. Fifty-eight cases were either intestinal or gastrointestinal type, which accounted for 90.6% of all the cases. In addition, there was an association between phenotype and biological behaviors (invasion or metastasis). The biological behaviors of intestinal and gastrointestinal type were better than gastric type. Compared with intestinal, gastric and gastrointestinal types, the biological behaviors of null type were the most aggressive. The biological behaviors of gastric carcinoma tended to be better as the number of expression of intestinal markers increased. Expression of markers related to the development and progression of cancer was not significantly correlated with phenotypes and biological behaviors of well-differentiated gastric carcinoma. Well-differentiated gastric adenocarcinomas are heterogeneous phenotypically. They can be divided into four phenotypes, namely intestinal, gastric, gastrointestinal and null types. Present findings show that well-differentiated gastric adenocarcinoma in the WHO classification is highly consistent with intestinal type gastric cancer in the Lauren classification. Expression of phenotypic marker is of certain clinic-pathologic significance.