CD40LG and neoplasm: To determine whether enforced transgenic expression of BCL2 and IL6 acts synergistically with loss of activation-induced cytidine deaminase (AID) to promote the expansion and malignant transformation of IgM-producing B lymphocytes, AID-deficient BALB/c (C) BCL2+IL6+AID− mice were monitored at weekly intervals for signs of tumor development, such as declining health status parameters and peripheral lymph node enlargements (Figure 1a).