SIRT6 and breast cancer: Moreover, SIRT6 promoted breast cancer metastasis by upregulating matrix metalloproteinase-9 (MMP-9) through the MAPK, NF-κB, and AP-1 pathways; silencing SIRT6 reduced cell invasion and migration in MCF-7 and MDA-MB-231 cells, suggesting its direct role in metastatic progression [145].