Evaluation of sensitivity and specificity of urine surviving as a new molecular marker in diagnosis of bladder tumors

Bladder cancer is one of the most common forms of cancers in the world. The current gold standards for its diagnosis are cystoscopy and urine cytology. Cystoscopy, a naked eye assessment of the bladder, is invasive, uncomfortable and costly with a great deal of personal variability in its results; while urine cytology has high specificity but low sensitivity, particularly for low-grade lesions. Therefore, there is a need for a molecular tumor marker assay capable of detecting bladder cancer with high sensitivity and specificity. A growing list of tumor markers in urine has been introduced so far, but neither of them has been able to replace the current diagnostic methods. Survivin, an inhibitor of apoptosis [IAP] capable of regulating both cell proliferation and apoptosis, has been recently defined as a universal tumor antigen and as the fourth most significant transcript expressed in human tumors. It has been reported to have 100% sensitivity and 95% specificity for detection of bladder cancer. In the present study, the sensitivity and specificity of survivin as a tumor marker in detecting new and recurrent cases of bladder cancer has been evaluated by nested RT-PCR technique. Our results revealed that survivin could be detected in most patients [11/13, sensitivity=0.84] as well as some healthy volunteers with no obvious sign of bladder cancer [6/13, specificity=0.53]. Also, in this work, for the first time, the presence of two alternatively spliced variants of survivin [survivin-2B and survivin-DEx3] urine is being reported. Interestingly, the presence of survivin-DEx3 was better correlated with malignant lesions of bladder compared to the survivin expression [sensitivity=0.84, specificity=0.92]