H2AX and cancer: Within cancer cells, the generation of ROS can cause DNA damage through double-strand breaks which can be assessed by immunofluorescent staining for phosphorylated histone H2AX (pH2AX) [19,20]; therefore, we assessed the ability of artesunate to induce DNA damage in A549 (resistant) and H1299 (sensitive) NSCLC cell lines in a dose-dependent manor.