Surface-enhanced laser desorption/ionization time-of-flight mass spectrometry (SELDI-TOF MS) for determining prognosis in advanced stage hormone relapsing prostate cancer

Prostate cancer frequently progresses despite early diagnosis and appropriate treatment with radical prostatectomy and/or radiotherapy. The clinical utility of SELDI-TOF MS to identify serum biomarker patterns associated with prostate cancer progression was examined by analysis of the serum proteome of advanced prostate cancer patients receiving standard androgen deprivation therapy. Serum from advanced-stage patients receiving androgen deprivation therapy was profiled by SELDI-TOF MS. Group 1 patients (n=15) had stable prostate specific antigen (PSA) responses to treatment; Group 2 (n=16) had rising PSA levels. Spectra were subjected to peak identification following total ion current (TIC) normalization. Peak intensities with m/z between 2,000 and 20,000 were tested for group differences via Kruskal-Wallis tests, and assessed individually for PSA-independent associations with overall survival via covariate-adjusted Cox regressions. TIC normalization yielded 53 useable spectra; 119 peaks with m/z between 2,000 and 20,000 were identified. Seven peaks showed statistically significant (p<0.05) differences between PSA groups, and several other peaks showed significant associations with overall survival independent of PSA status. In summary, SELDI-TOF MS captured a specific biomarker profile associated with biochemical relapse and provided additional prognostic information regarding long-term survival, independent of clinical PSA status.