SMARCA4 and ovarian small cell carcinoma: The concomitant somatic or germline mutation and epigenetic silencing of the mutually exclusive ATPase subunits SMARCA4 and SMARCA2, respectively, occurs in Small cell carcinoma of the ovary, hypercalcaemic type (SCCOHT), with SMARCA4 mutation reported in 69–100% of SCCOHT cases and SMARCA2 silencing seen 86–100% of the time.