We also found that serum ObR levels were positively correlated with serum CTLA-4 (p = 0.0056), TNF-α (p = 0.0025), PD-1 (p = 0.0023) levels as reported in breast cancer patients (39), and with serum PD-L1 levels (p = 0.0002). Here, CD274 is linked to breast cancer.