Gullo et al., 2019 [93], showed that significantly increased serum MPO levels were detected in HER2-negative breast cancer patients at 3 months (mean ± SD (1.627 ± 4.73), p < 0.05) of adjuvant treatment with docetaxel and cyclophosphamide in combination with bevacizumab compared to the baseline (mean ± SD (0.95 ± 1.47)). The gene discussed is MPO; the disease is breast cancer.