Importantly, sulindac and its metabolites modulate the expression of multioxidative enzymes, including glutathione S-transferases and NQO1, the latter being the key regulator of β-lapachone-induced cell death in cancer cells [28], [31], [32], and sulindac might therefore have a synergistic anti-tumor effect with β-lapachone. Here, NQO1 is linked to neoplasm.