DEAR DOCTOR K: I keep hearing about problems with the PSA test. Are any new screening tests for prostate cancer in development?
DEAR READER: Prostate-specific antigen (PSA) is a biomarker. Biomarkers are chemicals that can reveal that something abnormal is happening in the body. PSA is a chemical released by cells in the prostate gland. It is released at relatively high levels when prostate cells turn cancerous. However, PSA also is released in non-cancerous prostate conditions.