CDKN2A and colon adenoma: To determine the relation of cellular senescence to outgrowth of sympathetic nerves, The SFs density was detected [identified by tyrosine hydroxylase (TH) staining] in naturally aged male mice (24-month-old) and human colon adenoma tissues, two widely accepted aging models (Jin et al., 2014; Farr et al., 2017; identified by p16INK4A staining and SA-gal staining).