NQO1 and cancer: Since most compounds that correlated strongly with DPIQ anti-cancer activity gave modest PCCs of 0.38–0.55 to NQO1 expression, except for benzo[e]perimidine 3a, which was noticeably stronger (PCC = 0.64, Figure 1 and Figure 4), we searched for compounds with the strongest PCCs to NQO1 expression.