After the first dose course in the total breast cancer patients, PAM-Hb was significantly correlated with age (r = 0.365, p < 0.001), GFR (r =  −0.378, p < 0.001), and total given dose of cyclophosphamide (r = 0.292, p = 0.001) (Fig. 4). Here, GSTM1 is linked to breast cancer.