TP53 and acute lymphoblastic leukemia: Given the known importance of p53 in the response to critically eroded telomeres, we chose to conduct a genome‐wide CRISPR screen in the NALM‐6 pre‐B ALL cell line because it possesses wild‐type p53 and is well suited to large‐scale genetic screens owing to the ability to grow in suspension and a near‐diploid karyotype (Bertomeu et al., 2017).