AIMS

PBRM1 is one of the histone and chromatin regulators. A mutation in PBRM1 was recently identified in clear cell renal cell carcinoma (ccRCC). The aim of this study was to determine the clinicopathologic and prognostic significance of PBRM1 expression in ccRCC.

METHODS AND RESULTS

Immunohistochemistry was performed for PBRM1 in 657 ccRCC cases. The number of positive cells was determined using image analyzer after virtual microscope scanning. There was a strong correlation between decreased PBRM1 expression and old age, increased tumor size, higher Fuhrman grade, higher pT stage, and higher stage (all P <0.001). Patients with decreased PBRM1 expression showed significantly worse cancer-specific survival (CSS) and progression-free survival (PFS) (both P<0.001). In multivariate analysis, PBRM1 expression was an independent predictor of shorter PFS (P = 0.007). In lower-stage group (stages I and II), decreased expression of PBRM1 exhibited significantly worse CSS and PFS (both P<0.001) but not in higher-stage group (stages III and IV). In multivariate analysis of lower-stage group, decreased expression of PBRM1 was significantly associated with both poor CSS and PFS (P = 0.038 and 0.003, respectively).

CONCLUSIONS

Decreased expression of PBRM1 predicts unfavorable clinical outcome in patients with ccRCC.