CHEK1 and neoplasm: To examine whether similar effects were seen in other sarcoma models, we determined CHK1 levels in Rh18 and Rh10 tumor xenografts treated with AZD8055 and found that CHK1 was markedly downregulated by AZD8055 (Fig. 2D), a result similar to that of Rh30 xenografts (Fig. 2A).