LIN28B and pancreatic ductal adenocarcinoma: SIRT6 can bind to the promoter region of the lin-28 homolog B (Lin28b) gene and inhibit the expression of Lin28b through deacetylation, in which SIRT6 actively co-represses Myc-dependent transcription in human and murine pancreatic ductal adenocarcinomas specifically at the Lin28b locus, through deacetylation of the H3K56 and H3K9 chromatin marks.16