As shown in Fig. 2, Kaplan-Meier survival curves depicted that overall survival (OS) in NPC patients with Cks1 positive expression was shorter compared with the negative ones (P < 0.001, log rank =16.466) (Fig. 2a), but there was no significance between expression of p27kip1 and NPC patients survival rate (p > 0.05) (Fig. 2b). This evidence concerns the gene CDKN1B and nasopharyngeal carcinoma.