TM4SF1 and breast cancer: Overexpression of TM4SF1 significantly activated the phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT)/mammalian target of rapamycin (mTOR) signaling pathway, which acts through the downstream apoptosis-related proteins B-cell lymphoma 2 (Bcl2), BCL-2 associated X (Bax), caspase-3, and caspase-9 to induce anti-apoptotic effects in breast cancer (Sun et al., 2015; Wei et al., 2018).