While Bcl-xL has an anti-apoptotic function and is often upregulated in several cancers, Bcl-xS is a pro-apoptotic protein that antagonizes the survival functions of Bcl-xL.39 Although the splicing change of Bcl-x is small between BC200 KO and BC200 intact cells (Figure 5), the ratio of Bcl-xS/xL could be critical. This evidence concerns the gene BCYRN1 and cancer.