[The study of genetic changes in colorectal cancer accompanied with ulcerative colitis].

The usefulness of gene information was studied when used in conjunction with a morphological diagnosis of either dysplasia or carcinoma that later develops into ulcerative colitis (UC). The cases investigated consisted of those operated on for UC with carcinoma complications and those operated on for UC over 7 years previously without carcinoma complications. Ras and DCC were examined for the presence of any point mutations in codon 12 and polymorphism in codon 201 using the PCR-RFLP method, while p53 was also studied immunohistologically. A mutation in ras was found in 25% of the UC-IV cases and also in 17% of the UC-III cases, while no mutation at all was found in the UC-I and UC-II cases. p53 showed a high rate of positivity in the UC-IV and UC-III cases with carcinoma complications, while it was negative in all cases in the control group cases. Gly in DCC codon 201 was also found in many cases including the control group. This study demonstrated that a gene aberration can thus influence the pathophysiology and cancerization of UC and therefore the p53 findings were thus considered to be useful in the morphological diagnosis of dysplasia and carcinoma.