ERBB2 and breast carcinoma: In parallel, ObR is associated with an immunosuppressive status [66,73,74], observed in both breast cancer patients [75,76] and cats with mammary carcinoma, and is additionally correlated with the overexpression of cytotoxic T-lymphocyte associated protein 4 (CTLA-4), tumor necrosis factor-α (TNF-α) [64,77], and programmed cell death (PD-1)/programmed death ligand-1 (PD-L1) [64,78] in the most aggressive tumor subtypes (HER2-positive and triple-negative) [64,79].