Historically, the first evidence for a link between the mSWI/SNF complexes and cancer was shown in Malignant Rhabdoid Tumors (MRT), with the hallmark biallelic inactivation of SMARCB1, the gene coding for the BAF47 protein, observed in 98% of tumors (58–60). This evidence concerns the gene SMARCB1 and rhabdoid tumor.