Abstract
Human BCCIP, a protein which interacts with BRCA2 and CDKN1A (Cip1, p21), has been implicated in many cellular processes including cell cycle regulation, DNA recombination and damage repair, telomere maintenance, embryonic development and genomic stability. BCCIP gene expression, which is an important BRCA2 cofactor in tumor suppression, has been identified in some primary cancers. Thus, we investigated the role of BCCIP expression in a large sample of clinically diagnosed primary ovarian cancer, renal cell carcinoma (RCC) and colorectal cancer (CRC) tissues. Using clinically diagnosed frozen primary cancer tissues, quantitative PCR (qPCR), western blot analysis (WB) and immunohistochemical staining (IHC) approaches were used to detect and measure gene expression. Reduced BCCIP gene expression in ovarian cancer, RCC and CRC tissues occurred in 74, 89 and 75% of tissue samples, respectively. qPCR analysis of mRNA expression in 54 ovarian cancer, 50 RCC and 44 CRC samples revealed significant (>2-fold decreased) BCCIP downregulation in 56, 70 and 46% of tissue samples, respectively. Although BCCIP expression in three different tumor tissues decreased, the relationship between BCCIP expression and clinicopathological features of each cancer was distinct. Compared to normal tissues, BCCIP expression in ovarian cancers was significantly downregulated in serous, endometrioid and mucinous carcinomas. Downregulation of BCCIP expression was strongly associated with clear cell RCC (ccRCC) and Fuhrman tumor grading, but significant differences in BCCIP expression between CRC and matched normal tissues occurred only in male CRC tissues (p<0.05) and in tissue with a T4 tumor stage (p<0.01). Thus, BCCIP protein was chiefly reduced in ovarian cancer and RCC tissue samples (p<0.05). BCCIP gene expression was downregulated in human ovarian cancer, RCC and CRC tissues, suggesting a role for the gene in the pathogenesis of these cancers.