Abstract

We have investigated an immunohistochemical expression of the Human-Ha-ras oncogene product p21 in tumor cells of the primary mass and metastatic lymph nodes with different histological features of gastric cancer by using avidinbiotin complex immunoperoxidase method in formalin-fixed tissue sections from 73 cases of primary tumor mass and 23 cases of metastatic lymph node. Histologic type of the gastric cancer was classification. The results obtained were as follows: 1) Expression of Ha-ras p21 was consistantly increased in the well differentiated tubular adenocarcinoma as compared with poorly differentiated tubular adenocarcinoma (p<0.01), and was substantially decreased in mucinous carcinoma and signet ring cell carcinoma. 2) Signet ring cell carcinoma showed that positive immunoperoxidase reaction for Ha-ras p21 exhibited in the majority of immature signet ring cell with scant cytoplasm rather than in the mature signet ring cells which have abundant cytoplasm filled with mucin. This findings indicate that mucin production from the tumor cell was not correlated with activation of ras gene in the tumor tissue of gastric carcinoma. 3) In general Ha-ras p21 expression was enhanced in the metastatic tumor cells of the regional lymph node compared with primary tumor, especially it was consistantly increase in the well differentiated tubular adenocarcinoma.

• Keywords: Human-Ha-ras oncogene;Gastric cancer;Metastatic tumor;