[Detection and clinical significance of platelet derived growth factor-BB and microvessel density in clear cell renal cell carcinoma].

OBJECTIVE: To investigate the expression of platelet derived growth factor-BB (PDGF-BB) and microvessel density (MVD) marked with CD34 in clear cell renal cell carcinoma (CCRCC) and explore their relevance to clinicopathologic features and prognoses of patients.

METHODS: Expressions of PDGF-BB and CD34 in the tissue samples of 100 clear cell renal cell carcinomas were detected by immunohistochemical (IHC) SP staining. The microvessel density (MVD) was counted using Weidner's method. For PDGF-BB assessment, the staining intensity and the proportion of positive tumor cells were analyzed. Staining was considered immunoreactive when brown granules were identified in the cytoplasm or nuclei of tumor cells. Staining intensity and the proportion of positively stained tumor cells in lesions was scored for further analysis. Statistical analysis was performed using the software SPSS 18.0.

RESULTS: The MVD value marked by CD34 in the 100 cancer tissues was (105.49 ± 37.95) profiles/HPF. The median value of MVD in the entire cohort was used as the cut-off point for low MVD group (42 cases) and high MVD group (58 cases). The MVD of the low and high MVD groups was (75.12 ± 22.41) profiles/ HPF and (135.86 ± 22.91) profiles/HPF, respectively, with a statistically significant difference (P < 0.001). MVD was significantly correlated with the tumor T staging, histopathological grading and postoperative metastasis in CCRCC (P < 0.05, respectively). Among the 100 CCRCC cases, there were 38 cases with low PDGF-BB expression and 62 cases with high PDGF-BB expression, and the expression of PDGF-BB was significantly correlated with tumor diameter, T staging, histopathological grading and postoperative metastasis in the CCRCC (P < 0.05, respectively). Kaplan-Meier survival analysis showed that the cancer specific survival (CSS) in CCRCC patients with high expression of MVD and PDGF-BB was significantly better than that in the group with low MVD and low PDGF-BB expression (P < 0.001, respectively). Expression of PDGF-BB protein was positively associated with the MVD assessed by Spearman's correlation and factor analysis (r = 0.461, P < 0.001).

CONCLUSION: Significantly increased MVD and PDGF-BB expression detected in CCRCC patients indicate a better tumor grading and staging, and a longer survival time.