Chronic hypoxia (72h, 1% O2) actually modifies mitochondria morphology through a mitochondria fusion excess mediated by a HIF-1α, Mitofusin I, BNIP3, and BNIP3L dependent way in several cancer cell types (i.e., colon, lung, cervix, renal cancer cells). The gene discussed is HIF1A; the disease is cancer.