Lack of prognostic significance of p16 and p27 after radical prostatectomy in hormone-naïve prostate cancer

BACKGROUND: Loss of normal cell cycle control is an early event in the evolution of cancer. The expression of cyclin-dependent kinase (CDK) inhibitors p16 and p27 has been previously associated with progression of prostate cancer (PC). 70 patients diagnosed with early stage PCwere treated with radical prostatectomy (RP) at our institution and their tumor specimens were immunohistochemically evaluated for expression of p16 and p27. Available clinical data of time to PSA recurrence were correlated with the examined parameters and combined with pre-operative PSA level, Gleason score and pathological TNM (pT) stage assessment. RESULTS: Nuclear overexpression of p16 was not associated with time to biochemical failure (BF) (p = 0.572). Same was the case for nuclear p27 overexpression (p = 1.000). Also, no significant correlations were found between either p16 or p27, and pre-operative PSA level, pT stage and Gleason grade. pT stage emerged as the only independent prognostic factor for biochemical recurrence (p = 0.01). CONCLUSIONS: These data question previously reported data supporting the prognostic relevance of both p16 and p27 proteins in early PC.