TP53 and B-cell chronic lymphocytic leukemia: We functionally validated these findings with isogenic CRISPR/Cas9 generated models of del(11q) together with TP53 and/or ATM mutations, showing that CLL cell lines harboring biallelic loss of ATM and TP53 present abnormal cell cycle and mitotic profiles, failing to engraft and compete in murine xenotransplants.