The expression of Twist1 in tumor cells is modulated by several regulators including signal transducer and activator of transcription 3 (STAT3), nuclear factor kappa B (NF-κB), steroid receptor co-activator 1 (SRC1), Msh homeobox protein (MSX2), and Hypoxia-inducible factor 1-alpha (HIF-1α) [220]. The gene discussed is HIF1A; the disease is neoplasm.