Secondary genetic events (gene mutations and genetic lesions) in MCL are associated with genetic instability (ATM, 40–50% of cases, TP53, 15–20%), lead to cell cycle dysregulation (CDKN2A, 20–25%, CCND1, 20%, and MYC), induce changes in immune response and B-cell receptor signalling (CARD11, BTK, TLR2, S1PR1, and others), affect epigenetic and chromatin modifiers (SMARCA4, ARID1B, TET2, KMT2D, and others), dysregulate NOTCH signalling, and involve genes coding for protein ligases such as UBR5 [64]. The gene discussed is CCND1; the disease is mantle cell lymphoma.