Detection of high incidence of K-ras oncogenes during human colon tumorigenesis.

RNAse A mismatch cleavage analysis of 66 primary human colon tumors reveals a high incidence of K-ras genes with mutations at position 12. No apparent correlation was found between the presence of mutant oncogenes and the degree of invasiveness of the tumours but evidence for ras mutational activation in premalignant tissue was obtained.