Ma et al. Journal of Experimental & Clinical Cancer Research 2010, 29:85 http://www.jeccr.com/content/29/1/85 Table 3: Correlation of the expression of BMP-2 and its receptors with survival rate and survival time of ovarian cancer patients Positive expression rate (%) Negative expression rate (%) Five-year survival rate of positive cases Five-year survival rate of negative cases P value P value Survival time of negative cases Survival time of negative cases BMP2 62 38 40.32 18.42 0.023 37.27 ± 21.46 24.50 ± 22.47 0.006 BMPRIA 49 51 32.66 31.37 0.891 33.71 ± 21.95 31.18 ± 23.40 0.577 BMPRIB 62 38 41.94 15.79 0.007 37.66 ± 22.54 23.87 ± 20.25 0.003 Page 5 of 6 BMPRII 53 47 41.51 21.28 0.030 37.21 ± 22.10 27.02 ± 22.20 0.024 inhibitory effect of BMP-2 and BMPRIB may promote the development of ovarian cancer. It is possible that BMPRIA has no correlation with the development of ovarian cancer. That is, the development of ovarian can- cer is not due to the stimulatory effect of BMPRIA. In order to investigate the influence of BMP-2 on the prognosis of ovarian cancer patients, 100 patients were followed up after their surgery. Their five-year survival rate was 32%, a rate that is consistent with other pub- lished reports. Immunohistochemistry results demon- strated that ovarian cancer patients with positive expression of BMP-2, BMPRIB, and BMPRII exhibited remarkably higher five-year survival rates and average survival rates than patients with negative expression of BMP-2, BMPRIB, and BMPRII. BMPRIA showed no association with five-year survival rate or with survival time of ovarian cancer patients. BMP-2, BMPRIB, and BMPRII may play a part in the occurrence and develop- ment of ovarian cancer, and the variation or loss of Figure 3 Expression of BMP-2, BMPRIA, BMPRIB, and BMPRII in epithelial serous ovarian cancer detected by immunohistochem- istry (×400) A: BMP-2, B: BMPRIA, C: BMPRIB, D: BMPRII. expression of BMP-2, BMPRIB, and BMPRII may be an indicator of poor prognosis for ovarian cancer patients. Further studies conducted with larger sample sizes are needed to confirm this association. Our study suggests that BMP-2 and its receptors BMPRIB and BMPRII are likely to be involved in the development of ovarian cancer, and attenuation or loss of expression may result in or indicate poor prognosis for ovarian cancer patients. However, the specific pathway and mechanisms driving this effect need further study, if novel treatments for ovarian cancer are to be achieved through better understanding of its pathogenesis. Conclusions BMP-2, BMPRIB, and BMPRII exhibited a low expression in EOC tissue. The variation or loss of expression of these markers may indicate poor prognosis for ovarian cancer patients. Abbreviation list EOC: epithelial ovarian cancer; BMPs: bone morphoge- netic proteins; BMP-2: bone morphogenetic protein-2; BMPRIA: bone morphogenetic protein-2 receptor IA; BMPRIB: bone morphogenetic protein-2 receptor IB; BMPRII: bone morphogenetic protein-2 receptor II. Competing interests The authors declare that they have no competing interests. Authors' contributions YM carried out RT-PCR and Western blot, performed the statistical analysis and wrote the paper. LM participated in the design of the study and contributed with drafting the manuscript. QG carried out the immunohistochemistry stud- ies. SLZ participated in coordination. All authors read and approved the final manuscript. Acknowledgements This study was supported by China National Nature Science Fund (No.30100104) to Dr. Lin Ma. Author Details Department of Obstetrics and Gynecology, Shengjing Hospital of China Medical University, Shenyang 110004, China