In particular, MCL cells were shown to express TLR9, the receptor for CpG motifs within microbial DNA, and to respond with activation and enhanced proliferation when stimulated with CpG oligodeoxynucleotides.[15] Moreover, activation of TLR4 signaling by lipopolysaccharide was able to induce MCL cell growth and up-regulate production of IL-6, IL-10, and VEGF.[16] Nevertheless, MCL cells may variably express several other TLRs,[16] whose triggering by microenvironmental factors might contribute to the complex pathogenesis of this lymphoma. This evidence concerns the gene TLR9 and mantle cell lymphoma.