SF3A3 (splicing factor 3a subunit 3) is an essential component of the U2 snRNP spliceosome complex that mediates pre-mRNA splicing by promoting branch-site adenosine selection during the first step of splicing 1234. Within the SF3A subcomplex, SF3A3 contributes to 17S U2 snRNP assembly and subsequent formation of pre-spliceosome 'E' and pre-catalytic spliceosome 'A' complexes 12. The protein's expression is translationally regulated through an eIF3D-dependent mechanism involving an RNA stem-loop structure, particularly under MYC hyperactivation 5. SF3A3 demonstrates significant oncogenic properties across multiple cancer types. In endometrial cancer, it drives tumor progression by regulating alternative splicing of c-FOS, resulting in increased anti-apoptotic signaling and cisplatin resistance 6. Similarly, SF3A3 promotes breast cancer aggressiveness by facilitating metabolic reprogramming and stem-like properties 5, while in colorectal cancer it exhibits anti-apoptotic effects 7. Elevated SF3A3 expression correlates with poor prognosis in multiple cancer types 68. Therapeutically, phenethyl isothiocyanate (PEITC) has been identified as a direct SF3A3 inhibitor showing promise in preclinical studies 67.