INS and nasopharyngeal carcinoma: The fasting insulin level in the NPC group remained stable at GD0, GD4, and GD18, and it was significantly (p < 0.0001) decreased in the GDM group at GD4 and GD18 by 6.5 ± 0.7 U/mL and 8.2 ± 0.7 U/mL, respectively, as compared with the NPC group.