BERKELEY, CA (UroToday.com) - In our article we presented the increase of mRNA expression levels of four BMP ligands and three BMP specific receptors in renal cell carcinomas (RCCs), and BMP2, BMP6 and BMP7 were higher expressed in clear cell RCC while mRNA expression of BMP receptors was higher in non-clear cell RCC.
In our study expression of mRNA BMP2 in RCC was surprisingly high. BMP-2 has been reported to enhance migration, invasion and proliferation of the various types of prostate cancer cells, and motility and invasion of gastric cancer cells through the activation of phosphatidylinositol 3-kinase (PI3K)/Akt pathway.[1,2] That pathway has been included in epithelial-to-mesenchymal transition which is connected with migration and invasion of tumor cells.  The BMP2 has been found to be over-expressed in the majority of human lung carcinomas independent of cell type.[3,4] Our study particularly highlighted BMP2 expression, which was extremely elevated in CC-RCCs (53-fold higher than in normal tissue). The relative expression levels of BMP2 significantly increased with increased TNM stage. These considerably higher expression values in tumors with T3 stage indicated a possible association with tumor progression.
In exploring relationships between clinicopathological parameters and expression of different BMP ligands and BMP receptors, we have found that expression levels of BMP2 were up-regulated whereas expression levels of BMP6, BMP7 and BMPRIB were down-regulated in CC-RCC samples with higher tumor stage, stage T3-4. Long-term follow-up of our patients will show possible prognostic significance of this pattern of the expression levels.
It is not yet possible to draw unique conclusions about the roles of different BMPs and their receptors in RCC pathogenesis. Future studies are needed because published data are partly conflicting. We think that BMP2 is a promising factor with a potential role in RCC tumorigenesis, and is worthwhile for future investigation.
- Feeley BT, Krenek L, Liu N et al. Overexpression of noggin inhibits BMP-mediated growth of osteolytic prostate cancer lesions. Bone 2006;38(2):154-166.
- Kang MH, Kim JS, Seo JE et al. BMP2 accelerates the motility and invasiveness of gastric cancer cells via activation of the phosphatidylinositol 3-kinase (PI3K)/Akt pathway. Exp Cell Res 2010;316:24-37.
- Langenfeld EM, Bojnowski J, Perone J et al. Expression of bone morphogenetic proteins in human lung carcinomas. Ann Thorac Surg 2005;80:1028-1032.
- Langenfeld EM, Langenfeld J. Bone morphogenetic protein-2 stimulates angiogenesis in developing tumors. Mol Cancer Res 2004;2:141-149.
Dean Markić, MD, PhD, FEBU as part of Beyond the Abstract on UroToday.com. This initiative offers a method of publishing for the professional urology community. Authors are given an opportunity to expand on the circumstances, limitations etc... of their research by referencing the published abstract.