ζ-Stat trisodium (NSC37044 trisodium) is a potent and selective inhibitor of protein kinase C-ζ (PKC-ζ), exhibiting an IC50 of 5 μM. It effectively suppresses the proliferation of melanoma cell lines and promotes apoptosis. Moreover, ζ-Stat trisodium demonstrates notable antitumor activity in vitro.