[1695] Osteoactivin Expression in Normal Human Tissues, Prostatic Adenocarcinoma and Renal Cell Carcinoma, Clear Cell Type.

Guldeep K Uppal, Yajue Huang, Xinmin Zhang, Fayez F Safadi, Waixing Tang, Jasvir Khurana. Temple University Hospital, Philadelphia, PA

Background: Osteoactivin/Glycoprotein nonmetastatic B (GPMNB) is a bone morphogenic transmembrane glycoprotein synthesized by osteoblasts. Increased expression of osteoactivin is associated with osteoblast differentiation and matrix mineralization. Osteoactivin expression has been observed in cell lines of melanomas, meningiomas, hepatocellular carcinoma and is shown to promote metastatic and invasive potential in breast cancer, prostate cancer and gliomas via activation of metalloptroteinases. Exact role of osteoactivin in cancer expression and aggression is not clear at present. The aim of the study was to observe osteoactivin expression some normal human tissues, in malignancies with preferential osteoblastic (prostatic adenocarcinoma) and malignancies with preferentially osteolytic metastasis (Renal Cell Carcinoma, Clear Cell Type). To our knowledge till date there is no study reported in the literature on real human pathological tissues.
Design: Routine Hematoxylin and Eosin and immunohistochemical staining was performed on random sections of fetal bone, mature bone, small intestine, large intestine, breast, placenta and skin tissues, 18 cases of Renal Cell Carcinoma, clear cell type and 18 cases of adenocarcinoma of prostate. The anti-osteoactivin antibody (Human Osteoactivin/GPNMB MAb, R&D Systems) was used for this study.
Results: Osteoactivin staining in random tissue revealed a positive cytoplasmic staining in mature osteoblasts, small intestine epithelium, duct epithelial cells of breast, decidual cells of placenta and basal layer of skin. The staining was negative in colonic epithelium, stromal tissue of breast and chorionic Villi. 4 (22%) cases of renal cell carcinoma were positive for osteoactivin expression out of 18 cases. 5 cases (28%) of adenocarcinoma prostate were positive out of 18 cases.
Conclusions: Small intestinal epithelial cells, basal layer of skin, ductal epithelium of breast and decidual cells are immunoreactive for osteoactivin. There is no difference of osteoactivin expression between adenocarcinoma, prostate and Renal Cell Carcinoma, Clear Cell type. This is the first study that observed the expression of osteoactivin in actual human pathology tissue samples.
Category: Pathobiology

Wednesday, March 2, 2011 9:30 AM

Poster Session V # 226, Wednesday Morning


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