BCR and B-cell chronic lymphocytic leukemia: For instance, CLL subsets #1 and #4 do not only differ in disease outcome (subset #1 aggressive, subset #4 indolent) but are also characterized by distinct gene expression profiles of the TLR signaling pathway and distinct responsiveness to TLR ligands.38 These findings indicate that CLL cells receive prosurvival signals via both BCR-dependent and -independent pathways, with stereotyped subsets perhaps representing functionally distinct entities with distinct natural histories and patterns of cross-talk with the microenvironment.