BM-infiltrating NB cells secrete the cytokine TGF-β that modifies, in a dose-dependent manner, the expression of the chemokine receptors CXCR4, CXCR3 and CX3CR1 in NK cells present in the BM of children with NB, potentially affecting their activity [35]. The gene discussed is TGFB1; the disease is neuroblastoma.