ARHGEF1 and B-cell non-Hodgkin lymphoma: Similarly, mutations in ARHGEF1, which mediates the activation of RhoA in response to Gα13 and other receptors, have also been identified in GC-derived B cell lymphomas and, as mentioned above, the absence of ARHGEF1 in mice also results in the dissemination of GC B cells from the mesenteric lymph nodes into the periphery33.