Several epidemiological, diagnostic, and clinical studies have found that the majority of CYP genes are associated with the clinical efficacy of chemotherapy drugs in patients with BC; these genes include CYP1A2, 2A6, 2D6, 2S1, 3A4, and 3A5 [20,24,62,63], which were found to be deregulated in MCF-7/DOXR cells, in the present study. Here, PPIG is linked to breast cancer.