STAT3 and mantle cell lymphoma: STAT3 proteins bind phospho-Tyr1138 and are phosphorylated and translocated into the nucleus of dimeric units, activating the transcription of their targeting genes and leading to a huge variety of lymphomas, including DLBCL, unclassifiable diseases with features between DLBCL and Burkitt lymphoma, mantle cell (MCL), NK/T-cell (NKTCL), peripheral T-cell (PTCL), anaplastic large cell (ALCL) or intestinal T-cell lymphomas, as well as HL [135,136].