HIF1A and cancer: Since we could not identify which cancer cells were affected by HIF-1α or HIF-2α by measuring the expression levels of HIF-1α and HIF-2α, we determined that the cell viability decreased by knock down of HIFs under hypoxic conditions (Figure 1A); we confirmed HIF protein levels decreased by HIF-specific siRNA in Western blotting such as HIF-1α (Figure S3) and HIF-2α (Figure S4).