In the sense, we previously reported that CPT effectively inhibited phorbol myristate acetate (PMA)-induced invasion of prostate cancers by inhibiting matrix metalloprotease-9 (MMP-9) and vascular endothelial growth factor (VEGF) expression, which are downregulated by the upregulation of Nrf2-induced heme oxygenase-1 (HO-1), indicating that CPT suppresses cancer cell invasion without direct cytotoxicity [27]. Here, HMOX1 is linked to cancer.