Cytostatin sodium is an effective and selective protein phosphatase 2A (PP2A) inhibitor with an IC₅₀ value of 210 nM. Cytostatin sodium exhibits anti-metastatic properties, good antitumor activity, and can induce apoptosis. Cytostatin sodium can also prevent the adhesion of B16 melanoma cells to components of the extracellular matrix (laminin and collagen). Cytostatin sodium belongs to the family of natural product fosriecin^[1][2][3][4].