At 10 μM, CBP/β-catenin inhibitor provoked in fibrosarcoma HT-1080 and leiomyosarcoma SK-UT-1 the highest effect on the sub-G1 phase, thus raising cell death in vehicle-treated cells after 72 h 8- and 4-fold, respectively. Here, CREBBP is linked to leiomyosarcoma.