This event might be the consequence of the treatment-induced depletion of CD19+ tumor cells, which gives an advantage to subclones that do not express CD19 and gene rearrangements, such as lysine methyltransferase 2A/ALF transcription elongation factor 1 (KMT2A/AFF1) and zinc finger protein 384 (ZNF384) [126]. Here, AFF1 is linked to neoplasm.