In BC, the presence of CA IX in tumor tissue is significantly associated with impaired overall survival (OS) (HR = 1.90, 95% CI = 1.45–2.50), decreased disease-free survival (DSF) (HR = 1.74, 95% CI 1.34–2.27), worse disease-specific survival (DSS) (HR = 1.75, 95% CI 1.28–2.38), shorter metastasis-free survival (MSF) (HR = 1.76, 95% CI 1.13–2.74), shorter progression-free survival (PFS) (HR = 1.88, 95% CI 1.13 –3.10), and is also associated with a risk of locoregional relapse (HR = 1.37, 95% CI 0.95–1.96) [8]. The gene discussed is CA9; the disease is breast cancer.