Given that the patients were predominantly treated with chemotherapy and not with PD-L1 inhibitors, our findings may be compared with a claims database study using data from 2011 to 2017 (before the 2019 approval of atezolizumab) which reported mean all-cause total healthcare costs of $17 727 PPPM for patients with mTNBC during first-line chemotherapy, including a mean total BC-related treatment cost of $10 322 PPPM, compared with BC-related costs in our study of $11 333.25 This evidence concerns the gene CD274 and breast cancer.