Survivin gene-expression and splicing isoforms in oral squamous cell carcinoma

Purpose Survivin, an inhibitor of apoptosis protein and a cell cycle regulator, has been detected in the majority of human cancers. Five splice variants ( survivin, survivin-2 alpha, survivin-2B, survivin-3B, and survivin-Delta Ex3) have been identified; their expressions have been investigated here. Methods By means of RT real-time PCR and immunohistochemistry, we have evaluated survivin isoform expressions at both mRNA and protein levels in human normal oral tissue, precancerous lesions, and oral squamous cell carcinoma (OSCC). Their correlations with the pathological findings have also been analyzed. Results Expression levels of all survivin transcript variants were markedly elevated in OSCC when compared to normal tissues. One-way analysis of variance ( ANOVA) revealed highly significant up-regulation of survivin ( P = 0.001), survivin-Delta Ex3 ( P = 0.001) and survivin-2B ( P = 0.004), whereas survivin-3B showed a minor increase in OSCC compared to normal mucosa. Conclusions Our findings suggest that survivin isoforms deregulation may have significant implications in tumor aggressiveness and prognosis.