Mucin Phenotypic Expression and Submucosal Invasion of Gastric Differentiated-type Adenocarcinoma with Minimal Intestinal Metaplasia

Abstract

9.6% of all EGCs. Among those with a gastric phenotype, the rate of submucosal invasion was 62.5%, which was significantly higher than that in the incomplete intestinal-type cases (12.5%). CONCLUSION: Our results indicated that information regarding the mucin phenotypic expression is beneficial for predicting submucosal invasion of differentiated-type carcinoma surrounded by minimal IM. INTRODUCTIONGastric carcinoma is categorized into a number of diverse histological types, but there have been attempts to simplify the classification into just two groups based on the presence or absence of gland formation. Western countries have adopted Lauren's categorization system whereby gastric carcinomas are divided into diffuse-type and intestinal-type [1] , while Nakamura's classification into differentiated and undifferentiated-types has been mainly used in Japan [2] . The latter system divides gastric carcinomas into two groups based on not only gland formation, but also histogenesis, i.e., differentiated-type adenocarcinoma arises from gastric mucosa with intestinal metaplasia (IM), while undifferentiated-type adenocarcinoma is derived from the ordinary gastric mucosa without IM. ABSTRACT AIM: The gastric differentiated-type adenocarcinoma, which basically arises from intestinal metaplasia (IM), is occasionally derived from the ordinary gastric mucosa without intestinal metaplasia. However, in the clinical endoscopic field, it is still difficult to diagnose the invasion depth of differentiated-type adenocarcinoma surrounded by the ordinary gastric mucosa. The aim of our research was to clarify the prediction method of submucosal carcinoma invasion of these lesions. MATERIALS AND METHODS:The study population consisted of 282 early gastric cancer (EGC) lesions. The degree of histological IM in the background mucosa was classified according to The Updated Sydney System, moreover cases with normal and mild grades of IM were considered to have minimal IM. Mucin immunohistochemical staining was performed on 27 EGCs of the differentiated-type with background mucosa minimal IM, followed by classification into four mucin-phenotypes according to the expression of MUC5AC, MUC6, MUC2, and CD10.