In p27Kip1 knockdown HCT116 cells or MCF-7 cells, HF or ATS also up-regulated the expression of p21Cip1 and inhibited the active phosphorylation of CDK2, and those abnormalities were further manifested by the HF-AST combination treatment (Figure 5B, Figure S4B and S6). Here, CDK2 is linked to hydrops fetalis.