ARID1B and endometrial cancer: To define whether the dual loss of ARID1A/1B loss sensitized DDEC cell lines to the depletion of mSWI/SNF components, specifically, those corresponding to residual cBAF and PBAF complexes, we we used the ARID1A-deficient HEC1B endometrial cancer cell line in which we either treated with control CRISPR gRNAs or those targeting ARID1B, generating a dual ARID1A/ARID1B-deficient HEC1B cell line (Fig. 5C).