Figure 1. Local RAS predominantly localizes in the hypoxic tumor microenvironment.

(a) Expression analysis by ELISA (enzyme linked immunosorbent assay) of Ang II in the supernatant of hypoxic tumor cells (n = 3). (b) Ang II expression detection by IF (immunofluorescence) in in vitro tumor cells. (c,d) Ang II expression detection by confocal laser scanning microscopy in xenografted tumors in mice. (e) Ang II expression detection by IF in human nasopharyngeal carcinoma specimens. **P < 0.01, using a two-tailed, unpaired t-test. All experiments were performed at least thrice.