Foible No. 4B. The BPH effect obfuscates cancer specificity of PSA levels in
another way (B). On a gram-per-gram basis, the concentration of PSA in BPH tissue
is actually several fold higher than in CaP tissue. In the above study,
tissue PSA levels were measured in matched cancerous and benign tissues from
radical prostatectomy specimens. In almost every pair, the PSA level was much
higher in benign tissue than malignant tissue. Because of this difference,
PSA would not be expected to be a good cancer marker.