Amplification of the c-erb B1 oncogene in chemically-induced oral carcinomas.

The hamster cheek pouch is an excellent model for the experimental induction of oral tumor by chemical carcinogens. We have previously shown that the cellular oncogene c-erb B1 is overexpressed in the cheek pouch of the Syrian hamster when transformed by the carcinogenic chemical dimethyl-benzanthracene (DMBA). Here we report that this cellular oncogene is amplified in one such chemically-induced oral carcinoma (HCP-T12) and in a cell line (HCPC-1) established from a similarly derived tumor. Furthermore we present preliminary evidence that the gene amplification is most likely through an extrachromosomal pathway. These data together suggest that the amplification of the c-erb B1 oncogene might be responsible for its overexpression in these chemically-induced oral carcinomas.