Cancer of the prostate is the sixth most frequently found cancer in Singapore. Prostate-specific antigen (PSA) is the most clinically useful tumour marker available today for the diagnosis and management of prostate cancer. To enhance the value of PSA as a screening test we developed age-specific intervals for our ethnic population. The measurement of free PSA was included in the study to calculate the free:total ratio which enhances the differential diagnosis of prostate cancer from benign prostatic hyperplasia or prostatitis. The total PSA upper limits of 10-year intervals, beginning at 30-years-old, were 1.4, 1.7, 2.3, 4.0, 6.3 and 6.6 microg/l. Free PSA cut-off limits were 0.4, 0.5, 0.5, 1.0, 1.5 and 1.6 microg/l. The free:total ratio of PSA was not age dependent. Abbott AxSym standardised their calibration material for both free and total PSA assays with the Stanford 90:10 reference material. This laboratory has implemented these age-specific reference intervals and are currently following up their pick-up rate in the detection of prostate cancer.
Diagnosis of prostate cancer (PCa) is currently much reliant on the invasive and time-consuming transrectal ultrasound-guided biopsy of the prostate gland, particularly in light of the inefficient use of prostate-specific antigen as its biomarker. In the present study, we have profiled the sera of patients with PCa and benign prostatic hyperplasia (BPH) using the gel- and lectin-based proteomics methods and demonstrated the significant differential expression of apolipoprotein AII, complement C3 beta chain fragment, inter-alpha-trypsin inhibitor heavy chain 4 fragment, transthyretin, alpha-1-antitrypsin, and high molecular weight kininogen (light chain) between the two groups of patients' samples. Our data are suggestive of the potential use of the serum proteins as complementary biomarkers to effectively discriminate PCa from BPH, although this requires further extensive validation on clinically representative populations.