Mutations in various genes were observed to modulate tumor cell proliferation and progression in DLBCL cell lines at various cell cycle transition checkpoints: G0-S (BCL2), G1-S (RUNX1, ATM), G2-M (ATM, PIM2, FANCA), etc. Many of these genes, viz., BCL2, TP53, and PIM2, are also known prognostic markers for DLBCL. This evidence concerns the gene ATM and diffuse large B-cell lymphoma.