Structural diversity of cancer-related and non-cancer-related prostate-specific antigen.

BACKGROUND Heterogeneity among the various molecular forms of prostate-specific antigen (PSA) has not been well characterized, despite the critical importance of PSA in the detection of prostate cancer. The purpose of this study was to examine PSA heterogeneity in cancerous and noncancerous materials by extensive and systematic protein analysis. METHODS A catalog of molecular forms of PSA was established with the PSA purified from seminal fluid. This catalog was used to analyze PSA heterogeneity in cancerous and noncancerous materials by immunoblotting with polyclonal antibodies. RESULTS PSA from noncancerous materials showed a wider range of molecular mass, from 6000 to 28 000 Da. PSA from cancerous materials did not contain lower molecular mass forms. CONCLUSIONS The PSA protein catalog may be useful for the analysis of differences among PSA forms in men with and without prostate cancer and for analysis of antibodies used to detect PSA.