NFKB1 and neoplasm: These splicing factor mutations lead to changes in RNA splicing patterns, including global dysregulation of splicing, mis-splicing of subsets of genes involved in critical cell signalling pathways involved in tumorigenesis, and the promotion of tumorigenic isoforms of specific pre-mRNAs such as BRD9 (promotes tumours growth) and IRAK4 (hyperactivation of NF-κB signalling) (Inoue et al., 2019; Visconte et al., 2019; Wang and Aifantis, 2020).