ACTL6A and breast neoplasm: Analyses of human breast tumors indicate that SOX4 mRNA is uniformly overexpressed in basal-like tumors relative to adjacent normal tissue along with the SWI/SNF catalytic subunit SMARCA4 and SMARCB1 SMARCC1, SMARCD2, and ACTL6A, which encode for the essential subunits of this complex (Fig. 5b).