Mucin 1 (MUC1) is polymorphic transmembrane protein containing large extra cellular domain with variable number of highly conserved tandem repeats, aberrantly over expressed in most human carcinomas. Tumor suppressor protein, p53 is highly conserved, expressed in normal tissues and integrity of p53 function is essential for the maintenance of the non-tumorogenic phenotype of cells. Thus, p53 plays a vital role in suppressing the development of cancer. Tumor suppressor activity of p53 is reported by growth arrest of cells, DNA repair, senescence, differentiation or by apoptosis. It is reported that MUC1 promotes the arrest of growth to DNA damage by p53 dependent mechanism. The expression and regulation of p53 and MUC1 could be useful markers for metastatic potential tool for human carcinomas including breast and colorectal carcinomas.