To clarify the function of SIX1 on EMT in asthma, BEAS-2B and 16HBE cells were transfected with si-SIX1 before TGF-β1 treatment, and we observed that SIX1 level was up-regulated by TGF-β1 (P = 0.0003, P = 0.0002), but was down-regulated by following SIX1 deletion in BEAS-2B (P = 0.0005) and 16HBE (P = 0.0005) cells (Figure 5A). This evidence concerns the gene TGFB1 and asthma.