As was shown originally on a hepatocellular carcinoma cell line [112], calcium, in an ionomycin-inducible and 1,2-bis(o-aminophenoxy)ethane-N,N,N′,N′-tetraacetic acid (BAPTA)-sensitive fashion, potentiates secretion of vascular endothelial growth factor (VEGF) and transcriptional activity of the primary hypoxia response regulator, HIF1α, without changing the factor’s own expression level. Here, VEGFA is linked to hepatocellular carcinoma.