QPCR assay further suggested that CXCL1 administration could elevate the mRNA expression levels of stemness-related genes, including β-catenin, OCT4, and Nanog in breast cancer cells while abrogating the inhibitory effect of XPS on mRNA expression levels of the above genes in the co-cultured breast cancer cells (Figure 4C). This evidence concerns the gene CXCL1 and breast cancer.