The Detection of Prostate Specific Antigen, MHS-5, and Other Markers in Invasive Prostate Cancer and Seminal Vesicle

Abstract

Prostate specific antigen (PSA) is the most useful serum marker for following the disease status of prostate cancer patients after therapy. While PSA is felt to be an organ specific marker, lack of PSA expression in the seminal vesicles has not been adequately established. MHS-5 is a monoclonal antibody which recognizes an epitope on seminal vesicle specific antigen. Our objectives were to define PSA expression by the seminal vesicles, to determine whether MHS-5 could serve as an adjunct in the diagnosis of seminal vesicles invasion by carcinoma of the prostate, and to determine whether carcinoma, having invaded seminal vesicles would retain its expression of PSA and other prostate markers. Using an immunoperoxidase procedure, we studied thirteen seminal vesicles without histologic evidence of prostate cancer invasion and five seminal vesicles with locally invasive cancer. No seminal vesicles expressed PSA, whereas prostate cancer invading the seminal vesicles expressed PSA in all cases. MHS-5 expression was more variable. Only two of five cases of locally invasive tumor demonstrated seminal vesicles expression for MHS-5. Our findings further support the specificity of PSA. While MHS-5 may be helpful in delineating seminal vesicles in some instances, it is not a consistently reliable marker.

The effect of seminal vesicle‐sparing radical prostatectomy on serum prostate‐specific antigen level

“…Notably, one of the monoclonal antibodies used in both these studies [5,6] (‘ER‐PR8’) was also one component of the antibody mix used in the present study. In three older immunohistochemical studies of the seminal vesicle no PSA immunoreactivity was found [12–14]. We propose that these discrepancies are a result of differences in sample preparation, as all previous immunohistochemical studies [5,6,12–14] used either formalin‐ or Bouin‐fixed and paraffin‐embedded samples.…”

“…In three older immunohistochemical studies of the seminal vesicle no PSA immunoreactivity was found [12–14]. We propose that these discrepancies are a result of differences in sample preparation, as all previous immunohistochemical studies [5,6,12–14] used either formalin‐ or Bouin‐fixed and paraffin‐embedded samples. Using formalin‐fixed and paraffin‐embedded tissue we also obtained very weak and inconsistent PSA signals, hardly above background staining.…”

“…Previously it was reported that seminal vesicles with locally invasive prostate cancer express high levels of PSA immunoreactivity [14]. As our new surgical technique is restricted to organ‐confined disease, we only used normal specimens with no signs of seminal vesicle invasion.…”