There have also been reports on the impact of obesity on CTLA-4 treatment, where patients with BMI ≥ 25 (overweight or obese) had significantly improved response rates compared to patients with BMI < 25 (normal or underweight) who received ipilimumab as monotherapy for metastatic melanoma [56]. The gene discussed is CTLA4; the disease is obesity due to melanocortin 4 receptor deficiency.