HF alone inhibited 70.72 ± 2.66% of cell proliferation (IC70) at 5 nM, and in combination with 1 nM RAPA, the concentration of HF for IC70 was significantly decreased to 1 nM, as evidenced by 68.55 ± 0.85% in the combination of 1 nM RAPA with 0.625 nM HF or 71.98 ± 0.91% in 1 nM RAPA with 1.25 nM HF (HF alone vs. HF + RAPA: P ˂ 0.0001, two-way ANOVA, n = 5) (Fig 1E). Here, TRERF1 is linked to hydrops fetalis.