Expression of Seminal Plasma Proteins in Prostate Cancer: Prognostic Implications after Radical Prostatectomy.
Anastasia M Canacci, Koji Izumi, Yichun Zheng, Jennifer Gordetsky, Jorge L Yao, Hiroshi Miyamoto. University of Rochester, NY
Background: Seminal plasma proteins, semenogelins I (SgI) and II (SgII), have been shown to play a critical role in semen clotting and subsequent liquefaction in the presence of zinc and prostate-specific antigen (PSA). However, little is known about the role of semenogelins in human malignancies, including prostate cancer.
Design: We investigated the expression of semenogelins in four human prostate cancer cell lines by reverse transcription-polymerase chain reaction and western blotting as well as in 70 radical prostatectomy specimens by immunohistochemistry. We then evaluated the associations between the expression of semenogelins and clinicopathologic features available for our patient cohort.
Results: mRNA and protein signals for SgI and SgII were detected in androgen sensitive LNCaP cells cultured in the presence of 100 μM zinc, but not in the other lines, including androgen receptor (AR)-positive CWR22Rv1 cells and AR-negative PC-3 and DU145 cells. Immunohistochemical studies on prostatectomy specimens then showed that SgI and SgII stain positively in 55 (79%) and 31 (44%) cancer tissues, respectively, which was significantly higher than in corresponding benign tissues [SgI-positive in 13 (19%) cases (p<0.0001) and SgII-positive in 15 (21%) cases (p=0.0066)]. Of the 55 SgI-positive tumors, 28 (51%) were also SgII-positive, whereas 28 (90%) of 31 SgII-positive tumors were SgI-positive. Among the histopathological parameters analyzed, there was an inverse association only between Gleason score (GS) and SgII expression (GS≤7 vs. GS≥8: p=0.0150; GS7 vs. GS≥8: p=0.0111; GS≤6 vs. GS≥8: p=0.0674). Kaplan-Meier and log-rank tests further revealed that patients with SgI-positive/SgII-negative tumor have the highest risk for biochemical (PSA) recurrence (p=0.0242), although the expression status of either SgI alone (p=0.5409) or SgII alone (p=0.2378) was not strongly correlated with recurrence.
Conclusions: Our results suggest the involvement of semenogelins in prostate cancer and their prognostic values in predicting cancer progression after radical prostatectomy. Further functional analysis of semenogelins in prostate cancer is necessary to determine their biological significance.
Category: Genitourinary (including renal tumors)
Monday, February 28, 2011 1:00 PM
Poster Session II # 119, Monday Afternoon