In conclusion, the frequency of mutations in SPEN, SMARCA4 (SWI/SNF), RANBP2, KMT2C, NSD2 (WHSC1), Del 9p and/or Del 9q, CARD11, FBXW7, SP140, BIRC3, KMT2D (MLL2), PCDH10, CELSR3 and HNRNPH1 is much lower in indolent MCL. The gene discussed is SMARCA4; the disease is mantle cell lymphoma.