BNIP3 and cancer: Hypoxia also increases the ratio of fully spliced anti-apoptotic long Bcl-xL to alternatively sliced apoptosis-promoting short form Bcl-xS in cancer cells [160–163], and up-regulates alternative exon 3-skipped BNIP3 splicing, resulting in BNIP3 ΔEx3 isoform expression that is devoid of a mitochondrial localization signal and competes with pro-apoptotic fully spliced BNIP3 to promote survival [164–166].