MS4A1 and precursor B-cell acute lymphoblastic leukemia: High WT-CD20 transcript abundance further biased splicing toward the D393-CD20 isoform, indicating involvement of cryptic splice sites and potential re-splicing events at the level of mature <i>MS4A1</i> mRNA.<h4>Discussion</h4>Together, these findings are consistent with a model in which <i>NONO</i> expression and transcript-level dynamics of <i>MS4A1</i> are associated with CD20 heterogeneity in pediatric B-ALL.