RRM2 and nasopharyngeal carcinoma: As shown in Figures 2a and g, NPC cell line HNE1 and CNE2 were found to include low endogenous RRM2-c2orf48 levels and were used to establish RRM2-c2orf48 stable and overexpressed cell lines, which were confirmed by western blotting at the protein levels (Figure 5a).