OBJECTIVEResearch was done on the possible roles of beta-catenin, p53 and proliferating cell nuclear antigen (PCNA) in the carcinogenesis of colorectal adenoma (CRA).

METHODSbeta-catenin and p53 and PCNA expressions were studied with immunohistochemical stain in 77 specimens of CRA together with mild epithelial dysplasia (CRA-MD), CRA with moderate/severe epithelial dysplasia (CRA-D/SD) and CRA with cancerous changes (CRA-C).

RESULTSThe percentage of abnormal expression of beta-catenin increased during the transition from CRA-MD to CRA-D/SD to CRA-C (P < 0.01). The nuclear expressions of beta-catenin in CRA-D/SD and CRA-C were all significantly higher than that in CRA-MD. Expression of p53 and PCNA were increased from CRA-MD to CRA-D/SD to CRA-C, with the positive rates in these three groups of 10.3%, 43.8%, 75.0% for p53 and 17.2%, 62.5%, 87.5% for PCNA, respectively. 69.7% of cases with positive nuclear beta-catenin expression showed strong PCNA positivity which was much higher than the 36.4% of cases without nuclear beta-catenin expression (P < 0.05). The percentage of strong PCNA expression in the p53 positive cases was significant higher than that in cases with negative p53 expression (72.4% vs 37.5%, P < 0.05). Nuclear beta-catenin and p53 co-expression rates in CRA-C reached 50%.

CONCLUSIONbeta-catenin, p53 and PCNA may play important roles in the carcinogenesis of colorectal adenoma.