BCL2 and lymphoma: Whether this modulation of BCL-2 protein levels contributes to the capability to generate cell lines from these lymphomas or whether it is the cell of origin in which the transformation happens (immature B cell in our DHL-like model (Supplementary Fig. 9), compared to haematopoietic progenitors in the Eμ-Myc/Eμ-Bcl-2 model19) is not clear yet.