Clinical significance of MUC1 and MUC2 mucin and p53 protein expression incolorectal carcinoma

Background: Up-regulation of MUC1, down-regulation of MUC2 and p53 overexpr ession are seen in colorectal carcinomas. However, there have been few repo rts about the associations between MUC1, MUC2 and p53 expression and metast atic potential. The aim of this study was to investigate MUC1, MUC2 and p53 expression in colorectal carcinoma with special reference to regional and distant metastasis. Methods: Eighty-six colorectal carcinomas were collected from patients unde rgoing tumor resection. Sections were used for MUC1, MUC2 and p53 immunosta ining. Cancers were regarded as MUC1 or MUC2 positive when the positive cel ls were beyond 30% of cancer cells. Cancers with diffuse or nested patterns were regarded as having p53 overexpression. Results: Of 86 cancers, 37 (43%) were MUC1 positive, 28 (33%) were MUC2 pos itive and 59 (69%) showed p53 overexpression. A difference was observed onl y in the frequency of MUC1 positivity with respect to depth of tumor invasi on. Neither depth of tumor invasion nor histological differentiation had a positive correlation with MUC1, MUC2 and p53 overexpression. The frequency of MUC1 positive cells in Dukes' C and D tumors was significantly higher th an that in Dukes' A and B tumors. The frequency of MUC1 positivity in tumor s with hepatic involvement was significantly higher than that in tumors wit hout hepatic involvement (100 vs 39%; p < 0.01). There was no difference in the frequency of MUC2 or p53 positivity in Dukes' stage or hepatic metasta sis. MUC1 immunoreactivity of the surface was identical with that of the wh ole tumor in 81% (70/86) of carcinomas, MUC 2 in 87% and p53 in 100%. Conclusions: The results suggest that up-regulation of MUC1 is involved in the progression from the non-metastatic to the metastatic stage and that p5 3 abnormality is not directly involved in it. The data also imply that immu nostaining of preoperative biopsy samples is useful for evaluating the immu noreactivity of the whole tumor.