Oncogene expression in adenocarcinomas of the colon and in colon tumor-derived cell lines.

Six colon cancer cell lines, 13 colon tumors and ten normal colon tissues were analyzed for RNA expression using probes for c-myc, c-k-ras, c-myb, and c-fos and for the p53, TGF-alpha, and EGF receptor genes. No aberrant transcripts were detected. Levels of expression in tumors ranged from two-fold below that of normal tissue when the v-fos probe was used to 10 fold above the normal level when the c-myc probe was used. Enhanced c-myc expression was also observed in the cell lines. Southern and DNA dot blot analyses revealed c-myc amplification in three of the six cell lines.