For example, mutations in the splicing factor U2 Small Nuclear RNA Auxiliary Factor 1 (U2AF1), affects pre-mRNA splicing and contributes to the progression of cancer such as myelodysplasia (MDS) [32]; even with a single mutation such as S34F [33], which affects hundreds of mRNAs. The gene discussed is U2AF1; the disease is myelodysplastic syndrome.