In bladder cancer (HR = 0.65, p = 0.015), PAAD (HR = 0.52, p = 0.0018), and breast cancer (HR = 0.84, p = 0.00051, n = 4,929, GEO), the higher the expression of KCC2, the better the prognosis of the patient. The gene discussed is SLC12A5; the disease is urinary bladder carcinoma.