[Correlation between malignancy of gastric cancer and c-myc DNA amplification or overexpression of c-myc protein].

The amplification of c-myc DNA for fresh frozen tissue of 31 gastric adenocarcinomas was examined with dot blot hybridization method. Using the avidin-biotin peroxidase complex method, the expression of c-myc protein was examined immunohistochemically for formalin-fixed paraffin embedded tissue of 51 gastric adenocarcinomas including the same cases for c-myc DNA analysis. c-myc DNA amplification was detected in only 4 cases (12.9%). However, c-myc protein overexpression was recognized in 21 cases (41.2%). Only one of 4 cases showing c-myc DNA amplification indicated overexpression of c-myc protein. There was no statistically significant relation of c-myc protein overexpression with clinicopathological factors (histology, depth of invasion, invasion of the vessels, metastasis, intraabdominal dissemination and histological staging). These results suggest overexpression of c-myc protein could be recognized even in early gastric cancer indicating the relation of this gene product with proliferation of gastric cancer cells, although its role in the progression and metastasis of gastric adenocarcinoma might be minimal.