HIF-1α knockdown in breast carcinoma MCF-7 cells was shown to elevate the sensitivity to chemotherapeutic agent methotrexate [46] and resistance induced by hypoxia against doxorubicin and cisplatin in non-small cell lung cancer was reversed by silencing HIF-1α protein [47]. The gene discussed is HIF1A; the disease is non-small cell lung carcinoma.