H2AX and lung cancer: The immunofluorescent staining indicated that KRT7-AS-overexpressing tumor cells were highly susceptible to cisplatin, as indicated by high levels of γ-H2AX, a classic marker of DNA strand breaks (Fig. 4I), conversely, KRT7-AS-silenced lung cancer A549 cells showed a decrease in γ-H2AX levels (Fig. 4J).