Mutations at different gene loci in polyposis coli and carcinoma of the colon

At least six gene loci are involved in the
development of carcinoma of the colon associated
with polyposis coli. Somatic mutations
may occur in two recessive oncogenes (Ras
genes KRAS1 and KRAS2) and in four dominant
tumor suppressor genes. Most forms of carcinoma
of the colon are not associated with polyposis
coli.