Expression of survivin and its significance in colorectal cancer

AIM: To study the expression of survivin, a novel member of inhibitors of apoptosis protein (IAP) and its significance in colorectal carcinoma. METHODS: Survivin mRNA expression was evaluated by semi-quantitative reverse transcriptase polymerase chain reaction (RT-PCR) in 52 colorectal carcinoma samples and 48 adjacent normal colorectal tissue samples. PCR product was sequenced to verify the desired result. Expressions of survivin protein, proliferating cell nuclear antigen labelling index (PI) and apoptotic index (AI) were detected immunohistochemically in 52 human colorectal carcinomas. RESULTS: The expression of survivin mRNA was detected in a significantly greater proportion of colorectal carcinoma samples than in adjacent normal colorectal tissues (67.3% vs 25%; P<0.01). There was no relationship between survivin mRNA expression in colorectal carcinomas and sex, tumor size, histological types, lymphnode metastasis, distant metastasis and Dukes' stage. The PCR product shared 99% of homology with human counterparts. Survivin expression was observed immunohistochemically in 27 of 52 cases of colorectal carcinoma (51.9%). The AI was significantly lower in survivin positive group than in survivin negative group (0.67+/-0.18% vs 1.14+/-0.42%; P<0.001), while the PI was greater in survivin positive group than in survivin negative group (51+/-22% vs 27+/-18%, P<0.001). CONCLUSION: Survivin is a special tumor marker independent of histopathological characteristics. It may play an important role during human colorectal tumorigenesis by inhibiting apoptosis and accelerating proliferative activity of colorectal tumor cells.