In vivo studies on the liver metastasis of the hypoxia-tolerant tumor cell line L-CI.5s revealed the increased expression of HIF-1α and its signaling in syngeneic DBA/2 mice overexpressing TIMP-1 (Tissue inhibitor of matrix metalloproteinase-1), while the inhibition of HIF-1α led to a reduction in liver metastasis. The gene discussed is HIF1A; the disease is neoplasm.