Adenoma-carcinoma sequence of colorectum prevalence of k-ras gene mutation in adenomas with increasing degree of dysplasia and aneuploidy

One hundred and fifty colorectal adenomas were investigated in order to detect the presence of K-ras gene mutation. The adenomas were classified according to the severity of the histological lesion (mild, moderate, or severe dysplasia and carcinomatous transformation) and to the degree of aneuploidy. K-ras mutation was found in 30.8% of cases, mostly consisting of a point mutation of codon 12. K-rai mutation was more frequently found in adenomas >1 cm and in the villous type. No correlation was otherwise demonstrable with the ploidy pattern of the lesion.