BCL2L1 and neoplasm: In apoptosis regulation, hnRNP A1 competes with SR protein SRSF1 for binding to Bcl-x pre-mRNA, inhibiting the splicing of the pro-apoptotic Bcl-xS isoform while promoting the expression of the anti-apoptotic Bcl-xL isoform, thereby enhancing tumor cell survival 37.