In considering this ostensible disconnect, we would point out that type B comprises under 20% of FL at diagnosis, and that while pre-switch IgM+ type B tumors could presumably transform to either ABC-DLBCL (which are most often IgM/D + ) or GCB-DLBCL (which are most often IgG/A + )42, post-switch IgG+ type A tumors would presumably more likely give rise to an IgG+ GCB-DLBCL than an IgM+ ABC-DLBCL (at least directly). The gene discussed is CD40LG; the disease is diffuse large B-cell lymphoma.