TLR1 and mantle cell lymphoma: The further up-regulation of cyclin D1 expression after TLRs triggering is of particular interest, as the typical cyclin D1 over-expression that characterizes MCL is a necessary but not sufficient condition for lymphomagenesis.[1,2] Noteworthy, the analysis of this protein in four different primary MCL cultures after treatment with TLR1/2 or TLR5 ligands revealed a significant increase of its expression level also in this case (Fig 3B).