DNA amplification of the c-myc and c-erbB-1 genes in a human stomach cancer.

High-molecular-weight DNAs from 43 human primary tumor tissues were examined by Southern blot hybridization for possible rearrangement and/or amplification of the following protooncogenes: the c-myc, c-erbB-1, N-myc, c-mos and c-fos genes. In an adenosquamous cell carcinoma of the stomach, the c-myc and c-erbB-1 genes were found to be simultaneously amplified 5- and 30-fold, respectively. Cooperative expression of the amplified c-myc and c-erbB-1 genes might be involved in the genesis or progression of the gastric cancer.