Colon carcinoma K-ras 2 oncogene of a familial polyposis coli patient

The DNA of a colon carcinoma-derived cell line (KMS-4) and that of skin fibroblasts from a familial polyposis coli patient were transfected into NIH3T3 cells in order to detect oncogenes associated with the disease. No transformation was observed with the normal skin fibroblast DNA, while the KMS-4 cell DNA was able to transform NIH3T3 cells. Through hybridization with known oncogene probes, the KMS-4 transforming gene was found to be a human activated c-K-ras 2 oncogene. Sequence analysis of the molecularly cloned KMS-4 c-K-ras 2 oncogene showed a single nucleotide transition from G to T at the 12th codon. This results in substitution of cysteine for glycine at this position. On using labeled synthetic oligonucleotides to detect the mutation in codon 12, we found the G to T transition in colon carcinoma cells. This suggests that activation of the c-K-ras 2 oncogene could be associated with colon carcinoma induction.