An orally bioavailable, specific inhibitor of the canonical Wnt/beta-catenin signaling pathway, with potential antineoplastic activity. Upon oral administration, CBP/beta-catenin modulator E7386 inhibits beta-catenin and prevents the interaction of beta-catenin with its transcriptional coactivator, CREB (cAMP response element-binding) binding protein (CBP). This prevents binding of beta-catenin/CBP to WRE (Wnt-responsive element), and inhibits the activation of transcription of a wide range of target genes of Wnt/beta-catenin signaling, thereby preventing gene expression of many Wnt-related, pro-survival proteins and suppressing tumor cell growth. The Wnt/beta-catenin signaling pathway regulates cell morphology, motility, and proliferation; aberrant regulation of this pathway leads to neoplastic proliferation. Beta-catenin is frequently mutated in various tumors.