[Expression of the blood group related antigens (Lewis(a), Lewis(b), Lewis(x), Lewis(y), and other gastroenterological tissue related antigens(CEA, APF, and NSE) in poorly differentiated adenocarcinoma of gastric cancer with medullary growth pattern].

To clarify the clinico-pathological characteristic of poorly differentiated adenocarcinoma of gastric cancer with medullary growth pattern, the immunohistochemical study was performed using antibodies against blood group related antigens (Lewis(a), Lewis(b), Lewis(x), Lewis(y)) and gastrointestinal tissue related antigens (CEA, AFP and NSE). The following results were obtained. 1. Foveolar epithelium of normal gastric mucosa has type 1 blood group associated antigen (Lewis(a), Lewis(b)) and deep gland has type 2 antigen (Lewis(x), Lewis(y)) respectively, as the differentiation antigens. 2. Expression of Lewis(a) and Lewis(b) are more often observed in poorly differentiated adenocarcinoma with medullary and scirrhous growth pattern than in well and moderately differentiated adenocarcinoma. Poorly differentiated adenocarcinomas postulated to have closer relation with normal gastric deep gland in terms of antigen expression. 3. Poorly differentiated adenocarcinoma with medullary growth pattern is characterized as more differentiated type cancer than scirrhous type with respect to expression of blood group related antigen. 4. Poorly differentiated adenocarcinoma with medullary growth pattern may be divided into 3 subgroups by each antigen expression of CEA, NSE, and AFP.