Aberrant expression of nuclear phospho-protein BRCA1 in malignant canine mammary tumors

BRCA1 is regarded as putative tumor suppressor gene. This gene and its proteins are involved in the regulation of various critical steps of a cell cycle. A number of studies strongly suggest that the loss or aberrant expression of BRCA1 is associated with tumor formation. The present study was designed to investigate the immunohistochemical expression of BRCA1 in 31malignant canine mammary tumors (CMTs). Out of 31 cases, 26 cases showedcytoplasmic expression BRCA1 expression, whereas, in 5 casesno BRCA1 expressionwas observed. In addition, the BRCA1 expression was aberrant, as it was noticed in cytoplasm instead of nuclei of the tumor cells. The results of this study indicated that the loss or aberrant expression of BRCA1 might be associated with malignancy, and thus poor prognosis in CMTs.