Expression levels of heat shock protein 27 and cellular FLICE-like inhibitory protein in prostate cancer correlate with Gleason score sum and pathologic stage

PURPOSE Heat shock protein (HSP) 27 protects the cell by controlling apoptosis and immune reactions, and c-FLIP (cellular-FLICE inhibitory protein) inhibits apoptosis by inhibiting caspase-8 activity. We investigated the relationship of HSP27 and c-FLIP expression to prostate-specific antigen, Gleason score sum (GSS), and pathologic stage. MATERIALS AND METHODS Samples from 163 patients between May 2004 and April 2010 were analyzed: 83 from patients that had underwent a radical prostatectomy, and 80 from those that underwent transurethral resection of the prostate to alleviate urinary symptoms from benign prostate hyperplasia. c-FLIP and HSP27 expression were observed by immunohistochemistry staining. Samples with less than 5% expression-positive cells were scored as 1, with 5%-50% were scored as 2, and with more than 50% were scored as 3. Local reactions were identified as 0.5 and evaluated. RESULTS Both the presence of HSP27 within the tumor and the number of cancer cells positive for HSP27 were significantly correlated to GSS and pathologic stage (p<0.001, p=0.001, p<0.001, p<0.001). The same was true for c-FLIP expression (p<0.001). GSS was more highly correlated to HSP27 expression than to c-FLIP expression (r=0.814 for HSP27, r=0.776 for c-FLIP), as was pathologic stage (r=0.592 for HSP27, r=0.554 for c-FLIP). CONCLUSIONS In prostate cancer, higher GSS and a more advanced pathologic stage were associated with a higher likelihood of having a HSP27-positive tumor and more HSP27-positive tumor cells. HSP27 expression was correlated with GSS and prostate cancer stage. A more advanced pathologic stage corresponded to a higher likelihood of having a c-FLIP-positive tumor and more c-FLIP-positive tumor cells. HSP27 expression had a higher correlation with prostate cancer stage and GSS than c-FLIP expression did.