Hypoxic microenvironments lead to upregulation and stabilization of hypoxia‐inducible factors (HIFs), which are known to regulate expression of several genes (for example SNAIL, ZEB1, TWIST, matrix metalloproteinases, lactate dehydrogenase A and pyruvate dehydrogenase kinase 133, 34, 35, 36, 37, 38) that contribute to cancer progression, including many involved in cell survival, angiogenesis, glycolysis, cancer invasion, and metastasis. This evidence concerns the gene SNAI1 and cancer.