Background: Recent studies demonstrated that the expression pattern of bone morphogenetic protein-7 (BMP-7) is altered in different tumors. We determined expression of BMP-7 in human clear cell renal carcinoma (CCRC).
Methods: Samples from cancer and corresponding healthy tissue were obtained from 20 patients who underwent nephrectomy for CCRC. Expression of BMP-7 mRNA was determined by reverse transcriptase polymerase chain reaction (RT-PCR), and protein expression was analyzed by immunohistochemistry.
Results: RT-PCR showed strong down-regulation of BMP-7 mRNA in cancer tissue. Immunohistochemistry revealed expression of BMP-7 in normal renal tissue, with almost complete loss of BMP-7 expression in malignant cells of 6 patients (30%). After 3 years of follow-up, 5 out of 6 patients with high BMP-7 mRNA expression were alive and disease-free, compared with 9 out of 14 patients with low BMP-7 mRNA expression.
Conclusions: BMP-7 mRNA and protein expression were down-regulated in CCRC. Further prospective studies are needed to characterize the role of BMP-7 in human CCRC.