SMARCA1 and cancer: Studies have found that SWI/SNF subunit ARID1A deficiency attenuates mismatch repair (MMR) capacity, impairs mismatch repair in a variety of cancers, leads to genomic alterations in microsatellite instability (22, 23), increases TMB, increases neoantigen presentation, increases TILs, and makes tumors susceptible to immune checkpoint blockade.