Chromosomal breakpoint analysis has revealed that illegitimate immunoglobulin class switch recombination (CSR) is responsible for majority of the chromosomal translocations involving MYC in B-cell lymphomas, as these are often located in the IGH switch (S) regions that are targeted by activation-induced cytidine deaminase (AID) during CSR [55]. The gene discussed is MYC; the disease is B-cell non-Hodgkin lymphoma.