BMI1 and nasopharyngeal carcinoma: Real-time PCR and western blot analysis showed that IGFBP-1 and IGF-1 were differentially expressed at both the mRNA and protein level in 9 NPC cell lines (CNE1, CNE2, HONE1, HK1, SUNE1, 6–10B and 5–8 F, C666 and SUNE2) and 4 NPE cell lines (N5-Tert, N5-Bmi-1,N2-Bmi-1 and NP460) (Fig. 2a-c).