HIF expression and microvessel density in lung and colon cancer tumors. (A to C) Expression of HIF1α and 2α: Proteins were isolated from lung cancer tumors and colon cancer tumors and Western blot was performed for analysis of HIF expression. (A) Expression HIF1α mRNA and protein in lung cancer tumor; (B) Expression HIF1α in colon cancer tumor and (C) Expression of HIF2α protein in lung and colon cancer tumors. Left panels show quantitative data, setting normoxia as 1, and right panels show representative images of Western blot. n = 3 for each group. *p < 0.05 as compared with normoxia group. (D & E) Microvessel density: Immunohistochemical staining with CD31 antibody was performed to identify microvessels. Microvessel density in lung cancer tumors (D) and in colon cancer tumors (E). Left panels show quantitative data and right panels show representative images of immunohistochemistry (tumor from rats). Tumor = implanted tumor grown in rats. H-P-tumor = tumor from hypoxia-pretreated cancer cells grown in mice. Per HFP = average number of microvessels with CD31 positive staining/per high power field (× 200). n = 3 animals for each group. *p < 0.05 as compared with normoxia group.