CDKN2A and cancer: We further confirmed cellular senescence using another senescent marker, histone H3K9me3 (H3K9 trimethyl) (Figure S1C, Supporting Information).[21] Moreover, p16INK4A positive cells were positive for CDX2 immunostaining but negative for vimentin, indicating that these cells were not stromal cells but rather cancer epithelial cells (Figure S1D,E, Supporting Information).