CDKN1B and breast cancer: In agreement with its tumor-suppressing canonical function, p27KIP1 is downregulated in various cancer types, such as prostate cancer [115], lung adenocarcinoma [99, 116], colorectal carcinoma [117], bladder cancer [118], endometrial cancer [119], breast cancer [120], and glioblastoma [121], and this downregulation is associated with a worse prognosis and lower overall survival [121].