DKK1 and Bloom syndrome: As shown in Fig. 3a, c, the expression level of DKK1 and GSK3β protein in BLM + WYHZTL-H and BLM + XAV-939 group were significantly higher than that in BLM group (P < 0.001, P < 0.01, respectively), while BLM + WYHZTL-L and BLM + WYHZTL-M group didn’t have significant difference with BLM group (P > 0.05).