Unique expression of the xbp1 gene correlates with human prostate cancer

Unlike most of solid tumors, which have a range of molecular and/or immunological markers to help define prognosis and treatment options, prostate cancer (PCa) still mainly relies on histological grading and clinical parameters. Early detection of PCa is problematic due to the lack of a marker that has high diagnostic sensitivity and specificity. The X-box DNA binding protein 1 (XBP1) is a transcription factor that regulates expression of genes essential to appropriate functioning in the cellular stress response; yet little is known about the role of XBP1 in the progression of PCa. In the present study, we investigated the role of spliced XBP1 (S) and un-spliced XBP1 (U) in formalin-fixed paraffin embedded PCa tissues and PCa cell lines by using reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and western blot analysis. Results showed low expression of XBP1 (S) and XBP1 (U) isoforms both in vivo and in vitro. Moreover, there was no association between the developmental stages of PCa and expression of the two isoforms of the XBP1gene. The results may suggest initial evidence that XBP1 gene expression in human PCa is unique compared to other types of cancer, so could be used as a predictor marker for PCa. This may allow for hypothesis claiming apoptotic-escape mechanism underlying maintenance of malignant phenotype.