Munenori Azuma

Amplification and overexpression of the c-erbB-2 protooncogene in human gastric cancer.

SummaryThe c-erbB-2 protooncogene encodes a possible growth factor receptor. This gene has been studied as to whether it can be regarded as a prognostic indicator in human breast carcinoma. As amplification and overexpression of the gene have been reported in several adenocarcinomas, 24 specimens of human gastric cancers were examined by immunohistochemical staining (24 cases), by Southern blotting (23/24) and by Northern blotting (16/24). Amplification of the gene was detected in two moderately differentiated tubular adenocarcinomas (8.7%), and overexpression of c-erbB-2 m-RNA was detected in three moderately differentiated tubular adenocarcinomas (18.8%). By immunohistochemical staining of paraffin-embedded tissues using a polyclonal antibody to c-erbB-2 gene products, the cell membrane was stained positively in three cases of gastric cancers which overexpressed c-erbB-2 mRNA. Peritoneal metastases were found in six gastric cancers, including two moderately differentiated tubular adenocarcinomas in which amplification of c-erbB-2 occurred. These results suggest that amplification and overexpression of c-erbB-2 may be correlated with metastases in differentiated adenocarcinoma of the stomach.

Proliferating Cell Nuclear Antigen Expression in Colorectal Cancer According to the Depth of Invasion

Fifty eight cases of colorectal cancer treated in our department were classified into 4 groups according to the depth of invasion of tumor. In each group, proliferating cell nuclear antigen(PCNA) expression were compared between the superficial and deep part of the tumor. These results showed that the-differences in the positive rates between the superficial and deep portions tended to be greater in the more advanced cases, although those of the deep part were almost the same in all groups. It was suggested that proliferative activity of the superficial part of the tumor became to be decreased with the progression of the disease.