Recent work in mice demonstrated that few hours after injection into wild-type recipients, Eμ-TCL1 CLL cells migrate to follicles in a CXCR5-dependent manner and engage a cross-talk with follicular stromal cells via LTβR, resulting in CXCL13 secretion by stromal cells, leukemia activation, and proliferation25. The gene discussed is CXCR5; the disease is leukemia.