QKI represses ccRCC development by regulating the expression of HIF-1α and inhibiting angiogenesis. RT-PCR analysis showed that in the QKI overexpressing 786-0 (A) and caki-1 (B) cells, the HIF-1α,VEGF, GLUT-1, PGK-1 expression level was downregulated ,whereas in the QKI knock-down 786-0 (C) and caki-1 (D) cells, the HIF-1α, VEGF, GLUT-1, PGK-1 expression level was upregulated, the HIF-1α,VEGF, GLUT-1, PGK-1 expression level was even higher in hypoxia condition compare to normoxia condition. (E) VEGF protein level on QKI overexpression 786-0 and caki-1 cells. (F) VEGF protein level on QKI knockdown 786-0 and caki-1 cells. (G) HE staining (upper panel) and immunofluorescence(lower panel) of CD31 in nude-mouse transplanted tumor model (200×). (H) Microvessel count (MVC) of tumor mass. The data are presented as the mean ± SD and one -way ANOVA analysis for three independent experiments. * P < 0.05.