However, as demonstrated by bromodeoxyuridine (BrdU) incorporation, expression of proliferating nuclear cell antigen (PCNA), and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL), there was no difference in cell proliferation or apoptosis of tumor cells or normal crypt epithelial cells between 12 weeks old Zfp148gt/+ mice and controls, respectively (Figure 2A-2D and Supplementary Figure 2A, 2B). Here, PCNA is linked to neoplasm.