SOX2 and breast cancer: The heightened expression of tRF-19-W4PU732S derived from mature tRNA-Ser-AGA in breast cancer (BC) tissues and cells promotes EMT and cancer stem-cell (CSC) phenotypes, including upregulation of Octamer-binding transcription factor 4 (OCT-4A), SRY-box transcription factor 2 (SOX2) and Vimentin, as well as downregulation of E-cadherin, ultimately facilitating invasion and metastasis of BC cells (Zhang Z. et al., 2022).