Background: Up-regulation of MUC1, down-regulation of MUC2 and p53 overexpression are seen in colorectal carcinomas. However, there have been few reports about the associations between MUC1, MUC2 and p53 expression and metastatic 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 undergoing tumor resection. Sections were used for MUC1, MUC2 and p53 immunostaining. Cancers were regarded as MUC1 or MUC2 positive when the positive cells 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 positive and 59 (69%) showed p53 overexpression. A difference was observed only in the frequency of MUC1 positivity with respect to depth of tumor invasion. 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 than that in Dukes' A and B tumors. The frequency of MUC1 positivity in tumors with hepatic involvement was significantly higher than that in tumors without 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 metastasis. MUC1 immunoreactivity of the surface was identical with that of the whole 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 p53 abnormality is not directly involved in it. The data also imply that immunostaining of preoperative biopsy samples is useful for evaluating the immunoreactivity of the whole tumor.