The lymphoma type-specific protein landscape of splenic CD19 + B cells of SLE-prone mice was analyzed by western blot for the expression of BCL2, that together with c-MYC defines the class of “double expressor” lymphomas, and for IRF4, an additional marker belonging to the ABC-DLBCL signature. The gene discussed is BCL2; the disease is systemic lupus erythematosus.