Low-grade systemic inflammation is one of the characteristics of obesity [38], and RETN is shown to exert pro-inflammatory properties by upregulating pro-inflammatory cytokines [39] through the NFκB signaling pathway [40] that lead to inflammation and tumorigenesis. Several studies have also linked XRCC6 with an increased risk of BC [14, 41, 42]. The gene discussed is RETN; the disease is obesity due to melanocortin 4 receptor deficiency.