IDO1 and obesity due to melanocortin 4 receptor deficiency: Of those changes identified in the tumor microenvironments of ccRCC subjects with obesity versus non-obese counterparts, those with the largest fold changes were CD36 (+2.514, P = 0.045), IDO1 (+2.46, P = 0.012), CFB (+2.0, P = 0.041), CD7 (-4.66, P = 0.046), and CCL21 (-5.28, P = 0.0097).