Incidence of PHD2/3, HIF-α, and VEGF-A in ccRCC, head & neck and colon primary cancers. (A) Double immunohistochemical detection of HIF-1α and PHD2/3 in TMAs of ccRCC. Representative photomicrographs (all magnification x400) of HIF-1α positive and HIF-1α negative tumors (upper panel) showing nuclear staining of HIF-1α. Arrow indicates brown nuclear staining. Representative photomicrographs of PHD2 positive and PHD3 negative tumors (pink cytoplasmic staining, middle panel) and PHD2/3 negative tumors showing no cytoplasmic pink staining (lower panel). Numbers shown in the boxes are the positive/negative tumors. (B) Representative photomicrograph (x400) of HIF-2α positive tumors in TMA of ccRCC. Arrows indicate brown nuclear staining. (C) Percent incidence of PHD2, PHD3, HIF-α (HIF-1α and/or HIF-2α), and VEGF-A in ccRCC, head & neck, and colon primary tumor biopsies arranged in TMA. Numbers at the top of column indicate the number of positive cases among all evaluable cases. (D) Incidence of exclusively HIF-1α, HIF-2α and both HIF-1α and HIF-2α positive cases from the primary cancers in TMA. Some of the HIF-1α positive tumors turned out to be positive for HIF-2α and vice versa for HIF-2α positive tumors, which were excluded to count only HIF-1α, HIF-2α, and both HIF-1α and HIF-2α positive cases. The co-expression of HIF-1α and HIF-2α together was also significantly higher in ccRCC as compared to head & neck and colon cancers. Fisher Exact test revealed the statistically significant difference of incidence in ccRCC when compared to head & neck and colon cancers.*P < 0.001.