CA9 and cancer: Of importance for its utility as a cancer therapeutic target, CAIX is a critical, hypoxia-induced functional effector of several biological processes necessary for cancer growth and metastasis, including pH regulation and cell survival, migration and invasion, maintenance of cancer stem cell (CSC) function, development of the pre-metastatic niche and acquisition of chemo and radioresistant properties (McDonald et al., 2012; McDonald and Dedhar, 2014; Chafe and Dedhar, 2015; Pastorek and Pastorekova, 2015).