RAB1A and nasopharyngeal carcinoma: We also found that the expression of P-S6K1 protein was strikingly overexpressed in several NPC cell lines compared with in normal cell line NP69 (Figure 2A), but there was no significant correlation between Rab1A and P-S6K1 expression (r = 0.063, P = 0.863, Supplementary Figure 1C).