ABSENCE OF SERUM PROSTATE-SPECIFIC ANTIGEN AND LOSS OF TISSUE IMMUNOREACTIVE PROSTATIC MARKERS IN ADVANCED PROSTATIC ADENOCARCINOMA AFTER HORMONAL-THERAPY - A REPORT OF 2 CASES

We report two cases of advanced prostatic adenocarcinoma (PA) showing complete loss of three tissue immunoreactive prostatic markers, ie, pr ostate-specific antigen (PSA), prostatic acid phosphatase (PAP), and L eu-7 (CD57), with absence of elevated serum PSA level, despite tumor p rogression after hormonal therapy with or without radiotherapy. The pr etreatment serum PAP in the first case and serum PAP and PSA in the se cond case were elevated. In both cases, the prostatic adenocarcinoma i n the initial transurethral resection specimens showed positive immuno reactivity with three prostatic markers. After treatment, in both case s, the serum PSA were undetectable, and tumor cell immunostaining for three prostatic markers was negative. In addition, the posttreatment t umors in both cases showed increased number of tumor cells with neuroe ndocrine differentiation in comparison those in the pretreatment tumor s. Although early PA without elevated serum level of PSA is common, ad vanced PA with absence of elevated serum PSA, associated with presence of tissue immunoreactive prostatic markers are rare. This is the firs t report of advanced prostatic adenocarcinomas showing loss of tumor c ell prostate-specific markers with absence of elevated serum PSA level after hormonal therapy despite tumor progression. Copyright (C) 1996 by W.B. Saunders Company