DKK1 and Bloom syndrome: As shown in Fig. 5a, b and c, compared with BLM group, the protein level of Wnt1 and CTGF in BLM + WYHZTL-L, BLM + WYHZTL-M, BLM + WYHZTL-H and BLM + XAV-939 group were significantly downregulated (all P < 0.01; P < 0.05, P < 0.001, P < 0.001, P < 0.001, respectively), while DKK1 was upregulated (P < 0.05, P < 0.01, P < 0.01, P < 0.01, respectively), in which WYHZTL-H became more effective on promoting DKK1 (P < 0.001), while inhibiting Wnt1 and CTGF (all P < 0.001) than WYHZTL-M.