MCAT and breast cancer: Previous reports had revealed MT overexpression as a valuable prognostic marker for tumor progression and drug resistance in a wide range of cancers, such as ovarian cancer [22, 118], breast cancer [119, 120], small cell lung cancer [121], non-small cell lung cancer [122], renal cell carcinoma [123, 124], melanoma [24, 125], bladder cancer [23, 126], oral squamous cell carcinoma [127], and cholangiocarcinoma [128].