Statistically significant expression of B-myb in clinically advanced human renal-cell carcinomas

To find biologically critical factors for the tumor progression in human renal cell carcinoma (RCC), we examined expressions of c-myb and, c-myb homologous genes, A-myb and B-myb, in 34 primary human RCCs, normal kidneys and two metastatic tissues with Northern blot analysis. Seven cases (20%) exhibited positive B-myb expression. All 7 positive B-myb cases were associated with advanced stages and 5 of 7 cases had advanced metastasis. Interestingly, 2 metastatic tumors derived from the B-myb negative primary RCCs also exhibited B-myb expression. Statistical analysis proved that tumors with positive B-myb expression were significantly correlated with clinical stage III and IV (P<0.05). Four clinically advanced cases (12%) showed positive A-myb expression. These results suggest that B-myb gene expression might be involved in the progression of human RCCs. B-myb expression might be a good clinical marker for tumor aggressiveness and metastasis.