High incidence of coamplification of hst-1 and int-2 genes in human esophageal carcinomas.

We analyzed the alteration of the hst-1 and int-2 genes in 36 cases of esophageal squamous cell carcinoma, 42 cases of gastric adenocarcinoma, and 52 cases of colorectal adenocarcinoma. Coamplification of the hst-1 and int-2 genes was observed in 19 of 36 esophageal carcinomas (52%), 16 of 34 primary tumor tissues (47%), and 10 of 10 metastatic tumors (100%). The degree of amplification ranged from 4- to 8-fold. The incidence of hst-1 and int-2 gene coamplification was significantly higher in male patients than that in female patients (P less than 0.05). The coamplification of the hst-1 and int-2 genes had a tendency to correlate with clinical stage. The progesterone receptor gene, which is mapped to chromosome 11 at band q21-23, was not amplified in these esophageal carcinomas. Coamplification of the hst-1 and int-2 gene does not seem to imply increased numbers of chromosome 11, and the hst-1 and int-2 genes appear to be in same amplification unit on chromosome 11 at band q13. No coamplification of the hst-1 and int-2 genes was detected in gastric carcinomas and colorectal carcinomas. These results suggest that amplification of chromosomal locus of the hst-1 and int-2 genes might participate in carcinogenesis, in progression, and particularly in metastasis of esophageal carcinomas.