At the same time, the expression of chemokines (Cxcl9, Cxcl10) and the chemokine receptor CXCR3, which are key for traffic to the tumor and extravasation, were highly down-regulated in obesity, suggesting that lower chemokine levels prevented effective recruitment of immune cells to the tumor site. The gene discussed is CXCL9; the disease is obesity due to melanocortin 4 receptor deficiency.