SF3A3 and cancer: revealed that the separator helix of SF3A3 inserts into the gap between pre‐mRNA and U2 snRNA, stabilizing the pre‐mRNA–snRNA complex and supporting its core splicing function.[18, 33] Together, these findings, along with our work in EC, highlight SF3A3 not only as a structural component of the spliceosome, but also as a dynamic regulator of cancer‐specific splicing programs, with distinct oncogenic effects depending on tissue context.