Compared to paracancerous tissues, recurrent NPC samples only showed the significant reduction in fold change of CYP2B7P, while fold change of CYP2F2P, CYP4F26P, FCGR1CP and IGHV3–69-1 was not significantly altered (Fig. 7a-e, g), different from the expression pattern in primary NPC (Figs. 5b-d, g, h and 7f). Here, CYP2F2P is linked to nasopharyngeal carcinoma.