HIF1A and neoplasm: Our results showed that compared with the untreated control group, stable mRNA and protein expression of HIF-1α could be induced in Cal-27 and SCC-15 cells in a dose-dependent manner by CoCl2 under normoxia, as measured by qRT-PCR and Western blot respectively, which demonstrated the successful establishment of the hypoxic tumor microenvironment (Fig. 3A–C).