Background: Prostate-specific antigen (PSA) is a 33-kDa serine protease that is secreted by prostatic epithelium and non-prostate tissues. Ectopic expression of PSA has also been reported in a variety of non-prostatic epithelial tumors.
Patients and methods: Expression of PSA and its clinical implication were examined in a total of 422 cases of primary urothelial carcinoma of the bladder.
Results: Cytoplasmic reactivity to PSA was observed in 6 cases (1.4%), with the staining being to a low degree in 3 and a high degree in the remaining 3 cases. Expression of PSA was positively related to multiplicity, large tumors (> or = 3 cm) and muscle invasion (> or = pT2) (p = 0.0008, 0.004 and 0.03, respectively). Patients with tumors of low PSA expression had a better survival than those with tumors of high PSA expression (p = 0.03).
Conclusion: Focal expression of PSA can occasionally be detected in some large, invasive urothelial cancer cells. This phenotypic change should be considered in the differential diagnosis of poorly differentiated carcinoma of the lower urinary tract.