OLA1 and breast cancer: Previous observations have also shown that overexpression of OLA1 promotes tumor progression and causes poor survival in patients bearing hepatocellular carcinoma, colorectal cancer, endometrial cancer and lung cancer and that overexpression of OLA1 enhances drug resistance by inducing the epithelial-to-mesenchymal transition through activation of the TGF-β/Smad signaling pathway in breast cancer [29,30,32,33,34].