Previous studies have shown that S100A2 plays an anticancer role in oral cancer, prostate cancer, breast cancer, and lung cancer, while it acts as a cancer promoter in ovarian cancer, gastric cancer, and esophageal squamous carcinoma (Liu et al., 2000; Rehman et al., 2005; Bulk et al., 2009; Donato et al., 2013; Gross et al., 2014; Bresnick et al., 2015). Here, S100A2 is linked to breast cancer.