MRPL21 and breast cancer: Previous studies have linked five of the six copy number-associated genes in the 11q13.2-q13.3 region to cancer progression, including: 1) the genome amplification and overexpression of ORAOV1 and PPFIA1 associated with aggressive phenotypes in OSCC cell lines [20,25]; 2) the expression of the cell apoptotic signal mediator FADD associated with nodal metastasis in non-small cell lung cancer [26] and poor survival in laryngeal carcinoma [27]; and 3) the expression of CPT1A and MRPL21 associated with the development of colon cancer and breast cancer, respectively [28,29].