SIRT1 affected a variety of biological functions, including DNA repair, energy metabolism, tumor suppression, and mitochondrial homeostasis.30, 35, 37, 42 These effects have been linked to cell behaviors, involving cell growth, differentiation, migration, and survival.51 To date, the expression and role of SIRT1 has been under investigation and its expression has been identified in various tumors, including breast cancer and liver cancer.33, 34 Our sample analysis identified that the expression of miR‐181a was lower in tumors than nontumor tissues. The gene discussed is SIRT1; the disease is breast cancer.