MKI67 and nasopharyngeal carcinoma: A significantly lower density of Ki67+ cells per unit GFP+ graft area was detected in NPC transplants as compared to organoid transplants at both two and four weeks after grafting (p = 0.0014 and p = 0.0108, respectively), while there was no significant difference in organoid transplants between the two time points (p = 0.97; Fig. 6A,B).