NFE2L2 and neoplasm: Compare with tumors of the upper or middle thoracic part, the lower tumors had less contribution of sig6 (match to SBS18) that related to damage by reactive oxygen species, and correspondingly, the upper tumor compared to the lower tumor had a significantly higher mutational frequency of NFE2L2, which was responsible for antioxidant response and always had gain-of-function mutations (Fig. 6c, Supplementary Fig. 6b).