Cancer cells require nuclear-encoded components of mitochondrial OXPHOS to survive during glucose deprivation, whereas they activate glycolytic genes to support cell proliferation when glucose and nutrients are plentiful.31 Cellular adaptive response pathways promote the switch of gene expression profiles under nutrient stress.46 We found that ID2 enhanced mitochondrial membrane potential (Figures 5a and b) and suppressed mitochondrial OXPHOS and mitochondrial ATP production (Figures 5c, g and h). This evidence concerns the gene ID2 and cancer.