DPP4 and hepatocellular carcinoma: We examined the positivity of DXR‐treated HCC cells for established markers of cell senescence: p21, p53, p16 and DPP4.7, 11 p16 and p53 nuclear intensity levels were significantly increased in both HepG2 and Huh‐7 cells upon gradient‐based separation (Figures 4 and 5A‐C); HepG2 cells also showed an increase in p21 and DPP4 immuno‐positivity (Figures 4 and 5A‐C).