As shown in Fig. 1a, five NPC cell lines (SUNE1, 5–8F, S18, S26 and CNE2) had substantially higher ROR1 expression levels than the normal nasopharyngeal epithelial cell line (NP69), but all NPC cell lines showed considerably lower ROR1 transcription levels (<25fold) than those of the housekeeping gene, GPADH. Likewise, the 5T4 gene also has two transcript variants, but both of them encode the same protein. This evidence concerns the gene ROR1 and nasopharyngeal carcinoma.