Similar to the majority of cancers, CLL is a heterogeneous disease with a number of known genetic alterations, including the 17p deletion (del [17p]), the tumor protein 53 (TP53) mutation, and the 11q deletion (del [11q]), all of which have been identified as poor prognostic indicators in patients who have received chemoimmunotherapy [123,124]. The gene discussed is TP53; the disease is B-cell chronic lymphocytic leukemia.