Several studies have demonstrated that COL4A1 expression could be used as a biomarker for superior prognosis in BC patients receiving neoadjuvant chemotherapy [37], while epigallocatechin-3-gallate (EGCG) exerted antitumor effects by restoring nine key genes, including COL4A1, in myeloid-derived suppressor cells (MDSCs) [37]. Here, COL4A1 is linked to breast cancer.