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INTRODUCTION: Monocyte associated transketolase-like 1 (TKTL1) as a cancer biomarker has become popular with alternative practitioners, but plays no role in conventional medicine. This investigation evaluates the potential of serum TKTL1 as a biomarker for prostate cancer. MATERIAL AND METHODS: Patients (n = 66) undergoing curative radical prostatectomy (RPE) for biopsy-pro-ven PCa were included in the study. Controls (n = 10) were healthy, age-matched, male volunteers. 10 ml of peripheral blood was drawn from patients several days before surgery and from controls. Serum TKTL1 was measured using the ELISA method. RESULTS: The median age at tumor diagnosis was 66 years and median serum PSA was 8.0 ng/ml. Nearly 96% of PCas submitted to surgery were clinically significant. Compared to healthy controls, serum TKTL1 was significantly lower in PCa patients (p = 0.0001, effect size indicator r = Z/sqr(n) = 0.4179). No correlation was apparent between serum TKTL1 and serum PSA, Gleason sum, tumor stage or further clinical and pathologic parameters. CONCLUSIONS: Reduced serum TKTL1 in PCa patients stands in opposition to TKTL1 epitope detection in monocytes (EDIM) based studies, whereby increased TKTL1 in monocytes of tumor patients has been reported. Since serum TKTL1 does not correlate with clinical parameters in the current investigation, further research is needed to clarify whether serum TKTL1 has potential as a biomarker for PCa.
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BACKGROUND: Measurement of prostate-specific antigen (PSA) advanced the diagnostic and prognostic potential for prostate cancer (PCa). However, due to PSA's lack of specificity, novel biomarkers are needed to improve risk assessment and ensure optimal personalized therapy. A set of protein molecules as potential biomarkers was therefore evaluated in serum of PCa patients. METHODS: Serum samples from patients undergoing radical prostatectomy (RPE) for biopsy-proven PCa without neoadjuvant treatment were compared to serum samples from healthy subjects. Preliminary screening of 119 proteins in 10 PCa patients and 10 controls was carried out by the Proteome Profiler Antibody Array. Those markers showing distinct differences between patients and controls were then further evaluated by ELISA in the serum of 165 PCa patients and 19 controls. Uni- and multivariate as well as correlation analysis were performed to test the capability of these molecules to detect disease and predict pathological outcome. RESULTS: Screening showed that soluble (s)E-cadherin, E-selectin, MMP2, MMP9, TIMP1, TIMP2, Galectin and Clusterin warranted further evaluation. sE-Cadherin, TIMP1, Galectin and Clusterin were significantly over- and MMP9 under-expressed in PCa compared to controls. The concentration of sE-cadherin, MMP2 and Clusterin correlated negatively and that of MMP9 and TIMP1 positively with the Gleason Sum at prostatectomy. Only sE-cadherin significantly correlated with the highest Gleason pattern. Compared to serum PSA, sE-cadherin provided an independent and better matching predictive ability for discriminating PCas with an upgrade at RPE and aggressive tumors with a Gleason Sum ≥7. CONCLUSIONS: sE-cadherin performed most favorably from a large panel of serum proteins in terms of diagnostic and predictive potential in curatively treatable PCa. sE-cadherin merits further investigation as a biomarker for PCa.