RNA extraction from human MCF10CA1a tumors followed by real-time PCR using human-specific primers showed that Pirfenidone suppressed collagen I (COL1A1), hyaluronan synthase 2 (HAS2), hyaluronan synthase 3 (HAS3), collagen 3 (COL3A1), transforming growth factor-beta 1 (TGFβ1), and fibronectin (FN1) gene expression in breast cancer cells (Figure 6). Here, HAS2 is linked to breast cancer.