Secondly, we employed immunohistochemistry (IHC) to detect SIRT7 expression in 24-month-old naturally aged male mice and human colon adenoma tissues, and two commonly used and widely accepted aged models (identified by p16INK4A staining and SA-gal staining) (Yang et al., 2017; Yu A.Q. et al., 2020). This evidence concerns the gene CDKN2A and colon adenoma.