Enhanced expression of parathyroid hormone-related protein in prostate cancer as compared with benign prostatic hyperplasia.
Parathyroid hormone-related protein (PTHrP) has been shown to be the primary factor responsible for humoral hypercalcemia of malignancy. Recently PTHrP has been shown to be an early-response gene that may be involved in cellular proliferation or differentiation. In addition, PTHrP has been implicated in the pathogenesis of bone metastases. Bone metastases are a significant complication in patients with prostate cancer. We compared the expression of PTHrP by immunohistochemical staining using a monoclonal antibody directed against epitope between amino acids [53-64] in benign prostatic hyperplasia (BPH) with that in various stages of prostate cancer. Tissue sections were obtained on formalin-fixed paraffin-embedded blocks from BPH, well-differentiated prostate cancer, poorly differentiated prostate cancer, lymph node metastases (n = 15 each), and normal prostate (n = 2). In the normal prostate tissue there was no staining observed. In BPH, 13 of 15 tissue samples were positive for PTHrP immunoreactivity. An average of 33% of the cells stained positive with 1+ intensity. All samples from prostate cancer stained positive for PTHrP. In the samples from well-differentiated prostate cancer, an average of 87% of cells stained positive for PTHrP, whereas 100% of cells were positive in poorly differentiated and metastatic tumors. The intensity of staining was 3+ in well-differentiated tumors and 4+ in poorly differentiated tumors. Therefore, the expression of PTHrP is enhanced in prostate cancer as compared with BPH and is greater in poorly differentiated carcinoma as compared with the well-differentiated tumors. The role of PTHrP in the pathogenesis of prostate cancer deserves further study.
Asadi
F
F
Department of Medicine, VA West Side Medical Center, Chicago, Illinois 60612, USA.
Farraj
M
M
Sharifi
R
R
Malakouti
S
S
Antar
S
S
Kukreja
S
S
D000328:Adult; D000911:Antibodies, Monoclonal; D000939:Epitopes / Q000276:immunology; D006801:Humans; D007150:Immunohistochemistry; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D044162:Parathyroid Hormone-Related Protein; D011470:Prostatic Hyperplasia / Q000378:metabolism*; D011471:Prostatic Neoplasms / Q000737:chemistry* / Q000276:immunology / Q000473:pathology; D014176:Protein Biosynthesis; D013194:Staining and Labeling
D000911:Antibodies, Monoclonal; D000939:Epitopes; C470121:PTHLH protein, human; D044162:Parathyroid Hormone-Related Protein