CCR6 and neoplasm: Our group previously uncovered that in the intestine MCs provide support for the effector functions of B cells, both in physiology and inflammation.<h4>Methods</h4>In this work we investigated the relationship between the activation of MCs in CRC and recruitment and accumulation of B cells in the tumor environment.<h4>Results</h4>We observed infiltration of both B cells and MCs in the tumor tissue and uncovered accumulation of CCR6<sup>+</sup> B cells in tumor lymph nodes (LNs), both in the mouse model and in human patients.