RPS6KA6 and renal cell carcinoma: IHC staining of the RSK4 and CD34 proteins revealed that the microvessel density (MVD) was increased in RCC (Figure 2b); the correlation analysis revealed a positive correlation between RSK4 expression (H score20) and the MVD (Figure 2c, p = .009), suggesting that RSK4 may be involved in angiogenesis in ccRCC.