Schematic scenarios for the origin of follicular lymphoma, MCL, BL (MYC-IG single hit lymphomas), and DH lymphomas. (A) Follicular lymphoma; (B) MCL; (C) BCL2⁺/MYC⁺ DH lymphoma with 2 scenarios, one with an origin from relatively common benign “follicular lymphoma–like B cells” that can be detected in most healthy persons, and the other from a preexistent follicular lymphoma. (D) CCND1⁺/MYC⁺ DH lymphoma with 2 scenarios, one with an origin from rare benign “MCL-like B cells” that can be detected in few healthy persons, and the other from a preexistent MCL. (E) BL; (F) BCL6⁺/MYC⁺ DH lymphoma with unknown order of events. For readability possible occurrence of the t(14;18) at later stages of B-cell development (including the GC) and (secondary) involvement of RAG1/2 and/or other mechanisms herein are not displayed in the figure (see “Oncogenes involved in DH lymphomas”). AICDA indicates activation-induced cytidine deaminase; RAG1/2, recombinase activating gene 1/2. Not drawn to scale.