SIRT6 and cancer: Our observations also suggest a model of SIRT6 function similar to the “feed-forward” loops of transcriptional regulation [48,49], in which an input (here SIRT6 activity) feeds into two processes (histone deacetylation and suppression of acetyl-CoA precursor for histone acetylation) that both contribute to maintaining the repression of cancer cell gene expression programs (Figure 4).