Inactive free : total prostate speci®c antigen ratios in ejaculate from men with suspected and known prostate cancer, compared with young control men Objective To measure free : total prostate speci®c antigen (PSA) ratios in ejaculate from men with suspected and known prostate cancer, and in young control men, to determine if this ratio might be useful in discriminating benign from malignant prostatic conditions. Patients, subjects and methods Forty-seven men with prostate cancer (positive biopsies), 52 men with suspected prostate cancer but who had negative biopsies and 28 young men (<30 years old) and with no family history of cancer, provided either a single ejaculate specimen (total 59) or multiple specimens (total 193) on subsequent occasions. Free and total PSA were measured using appropriate assays. All specimens were diluted in a PSA-negative female serum pool. Results The median free : total PSA ratios were 0.76±0.81 among the patient groups and control men, and there was no statistical difference between the groups. These data presumably only re¯ect the inactive component of free PSA, given that any a 2 -macroglobulin or a 1 -antichymotrypsin in the assay serum diluent was likely to have bound the active free PSA component in these samples. Similar results were obtained from those providing single and multiple samples, suggesting that a single specimen is suf®cient to re¯ect the seminal plasma free : total PSA ratio over that period. There was no relationship between seminal plasma free : total PSA ratio and age for the controls or the positive biopsy group, although there was a negative relationship (i.e. a decline with age) that almost reached signi®cance in those with negative biopsies (P=0.058, R 2 =0.07). Conclusions This is the ®rst report of free : total PSA ratios in the ejaculate of men with suspected and known prostate cancer compared with young control men. Although no signi®cant changes were detected in the free : total PSA ratios in ejaculate, these results may be confounded by differences in ratios with age, as is the case for serum PSA or different molecular forms of PSA. Indeed, these data suggest that a large proportion of free PSA in seminal plasma may be inactive. Further studies are needed to determine the potential utility of measuring free : total PSA, or other candidate markers, in ejaculate to better discriminate benign from malignant prostate disease.

No abstract

No abstract

No abstract