This gene is constituted by 3 exons with the ability to generate 2 isoforms due to the selection of two alternative 5’ splice sites in exon 2, resulting in isoforms BCL-XL (B-Cell Lymphoma xtra large) and BCL-XS (B-Cell Lymphoma xtra small). Here, BCL2L1 is linked to B-cell non-Hodgkin lymphoma.