TLR1 and mantle cell lymphoma: The heterogeneous expression of TLRs is also consistent with the highly heterogeneous level of responses to TLR activation observed among different lymphomas and even on a patient-to-patient basis.[10] Consistently, MCL cell lines cultured in the presence of TLR1/2 or TLR5 ligands exhibited enhanced proliferation with a variable extent of response to each stimulus among the cell lines investigated.