CA9 and neoplasm: To identify potential co-vulnerabilities of hypoxic tumor cells to inhibition of CAIX, which could be exploited to prevent, or suppress, resistance and recurrence, a recent genome-wide synthetic lethal approach in triple negative breast cancer cells revealed that hypoxia induced CAIX activity suppresses ferroptosis mediated cell death, and that inhibiting CAIX renders tumor cells more vulnerable to compounds that induce ferroptosis [32].