Here, for the first time, we show that CPX, at low concentrations (≤5 μM), also reduced the cellular protein level of Cdc25A, which resulted in increased inhibitory phosphorylation of G1-CDKs, leading to the accumulation of cells in G1 phase of the cell cycle in breast carcinoma (MDA-MB-231) and rhabdomyosarcoma (Rh30) cells. Here, CDC25A is linked to breast carcinoma.