Remarkably, inhibition of SIRT7 also enhanced the repression of ARF target genes in ARF-positive Calu-3 lung cancer cells (SI Appendix, Fig. S4B) further supporting the hypothesis that SIRT7 controls expression of Nectin2, XRCC1, and SUPT5H in an ARF-dependent manner. This evidence concerns the gene XRCC1 and lung cancer.