By using the (CRISPR)/Cas9 technology, they demonstrated that the simultaneous inactivation of CDKN2A, CDKN2B, and TP53 in primary TCL1 transgenic-derived murine CLL cells induces proliferation in vitro and accelerates tumor growth in the TCL1 tg transplantation system. The gene discussed is CDKN2A; the disease is B-cell chronic lymphocytic leukemia.