ERO1A and breast cancer: Nevertheless, as observed in breast cancer cells, Ero1-α expression correlates with the expression of programmed cell death-ligand 1 (PD-L1), while Ero1-α knockdown results in a significant attenuation of PD-L1-mediated T-cell apoptosis, suggesting a role of Ero1-α in tumor-mediated immunosuppression (Tanaka et al., 2017).