SMARCA2 is an ATP-dependent catalytic subunit of the SWI/SNF chr9 remodeling complex that regulates gene expression by altering chr9 structure 1. The protein functions by engaging with and pumping DNA along nucleosomes upon ATP hydrolysis, facilitating transcriptional activation and repression 1. SMARCA2 plays a critical role in neural development as a component of both neural progenitor-specific (npBAF) and neuron-specific (nBAF) chr9 remodeling complexes, with complex composition switching during neuronal differentiation 2. In cancer biology, SMARCA2 exhibits a synthetic lethal relationship with its paralog SMARCA4, where SMARCA4-mutant cancer cells become dependent on SMARCA2 for survival 34. This dependency makes SMARCA2 an attractive therapeutic target, as selective SMARCA2 degradation shows efficacy in SMARCA4-deficient tumors 53. The protein is particularly important in enhancer-driven cancers like prostate cancer, where SMARCA2/SMARCA4 degradation disrupts oncogenic enhancer circuitry and transcription factor binding 6. Additionally, SMARCA2 contributes to thyroid cancer differentiation through chr9 remodeling at thyroid transcription factor enhancers 7. Clinical significance includes potential as a biomarker and therapeutic target in various cancers with SMARCA4 mutations.