Stat3 inhibitor III, WP1066 (WP10666) is a cell permeable AG 490 tyrphostin analog that effectively inhibits the STAT3 pathway. The inhibitor is a potent antitumor agent as displayed in the growth inhibition of malignant glioma cell and acute myelogenous leukemia cells. Stat3 Inhibitor III, WP1066 has shown more potency as an antitumor agent than AG 490 when inhibiting malignant glioma growth in vitro. WP1066 also acts as an immune adjuvant by inducing proliferation of effector T cells and upregulating CD86 and CD80. In addition WP1066 has displayed inhibition of JAK2 protein tyrosine kinase as well as suggested activation of Bax.