Downregulated genes (> 3-fold) had functions in breast cancer (cathepsin D, KRT5, and MAPK1), apoptosis (TNFSF8), drug resistance (ABCC3, ABCG2, and EGFR), tumor metastasis (CD44, EPHB2, ETV4, IL-18, MMP3, and MMP13), epithelial–mesenchymal transition (EMT; Caveolin-2, FGFBP1, integrin alpha 5, and SERPINE1), angiogenesis (CTGF, Fibronectin 1, ID1, IL1B, and IL6), and included stem cell transcription factors (HOXA7, KLF4, PCNA, POU5F1, SOX9, and STAT3) (data not shown). This evidence concerns the gene PCNA and breast cancer.