We also detected PD-1hi, PD-1lo and PD-1− populations among CD8+ T cells with a significant accumulation of the PD-1hi and depletion of PD-1lo population within CD8+ T cells from intermediate 8 mos post-DEN HCC tumours compared to 6 or 12 mos post-DEN tumours (Fig. 6e, f). The gene discussed is CD8A; the disease is hepatocellular carcinoma.