This notion is supported by results from a currently ongoing Phase 1 study of ABT-199 in refractory chronic lymphoid leukemia patients [24], showing that similar objective response rates (ORR) (78%) were achieved in patients harboring chromosome 17p deletions (thus p53 deletion) with or without p53 mutations of the remaining allele, as compared to the ORR (79%) for the entire group. This evidence concerns the gene TP53 and lymphoid leukemia.