Surprisingly, using the pan-caspase inhibitor Z-VAD, the cell apoptosis in (−)-Guaiol treated A549 cells was similarly suppressed as 3MA (Supplementary Figure S4A and S4B), implicating that the RAD51 deficiency generated DSBs triggered cell apoptosis in (−)-Guaiol treated NSCLC cells by increasing caspase activities. Here, RAD51 is linked to non-small cell lung carcinoma.