[868] MUC1 Immunohistochemical Staining of Ductal, Cribriform and Noncribriform Gleason Grade 4 Acinar Adenocarcinomas of the Prostate and Its Comparison in pT2 Versus pT3

M Herawi, JI Epstein. Wayne State University, Karmanos Cancer Institute & Harper Hospital, Detroit, MI; Johns Hopkins Medical Institution, Baltimore, MD

Background: Overexpression of MUC1, a membrane-bound high MW glycoprotein, has been suggested to be associated with higher grade and stage prostate cancer. We studied the immunohistochemical expression of MUC1 in cribriform and noncribriform acinar Gleason grade 4 and in ductal prostatic adenocarcinoma (PCa) versus benign prostatic glands. In addition, MUC1 expression was compared in pT2 versus pT3 cancers where staging information was available.
Design: Two paraffin Tissue Micro-Arrays (TMA) were used to evaluate 742 tissue samples (0.6-mm-diameter): 106 cribriform acinar and 134 noncribriform acinar Gleason Grade 4 PCa, 139 ductal PCa, and 202 benign prostate tissues. Among included control tissues were 20 benign seminal vesicles. Immunohistochemistry was performed using a monoclonal antibody against MUC1 (Novocastra, clone Ma695). Moderate to strong focal and patchy or diffuse staining was considered positive. Tumors with known pathologic stage were grouped accordingly and MUC1 staining was compared in pT2 versus pT3 groups.
Results: 64% of noncribriform acinar, 51% of ductal and 41% of cribriform PCa stained positive for MUC1 compared to 40% of benign prostatic glands. Luminal/apical staining pattern in benign was in contrast to often cytoplasmic/luminal staining in cancerous glands. Among all tumors, 51% of pT2 showed positivity compared to 56% of pT3 cancers. Among the ductal PCa, 47% of pT2 were MUC1 positive versus 61% of pT3 cancers.
Conclusions: 1) MUC1 staining was seen in 52% of all PCa compared to 40% of benign prostatic glands. 2) While 64% of noncribriform acinar Gleason grade 4 PCa and 51% of ductal PCa showed positive staining for MUC1, only 41% of cribriform Gleason grade 4 PCa were positive. 3) There was no significant difference in MUC1 staining between pT2 (51%) and pT3 (56%) prostatic adenocarcinomas. 4) Staining pattern in cancerous glands was often cytoplasmic/luminal compared to luminal/apical staining in benign glands. 5) In contrast to 40% of benign prostatic tissue, all samples of benign seminal vesicle tissues (100%) were positive for MUC1.
Category: Genitourinary (including renal tumors)

Monday, March 22, 2010 1:00 PM

Poster Session II # 123, Monday Afternoon


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