MYD88 and diffuse large B-cell lymphoma: Consistent with this result, PD-L1 levels were higher in two activated B-cell (ABC) DLBCL, a subset of which have driver mutations that activate BCR and MyD88 signaling, than in tumors of the germinal center B-cell subtype, which tend to have lower levels of BCR and TLR signaling (Fig. 3D).