Abstract: Objective To investigate the expressions of CK，Tubulin-β and PCNA in nasopharyngeal carcinoma(NPC) and the possible mechanism of NPC recurrence and metastasis after radiotherapy. Methods Experimental nude mice transplanted NPC F1 and S1 cell exposed to radiation.Cell morphology，proliferation and metastasis in vivo analyzed.CK，Tubulin-β and PCNA were detected using immunohistochemical SP method in nude mice transplanted tumor tissue and recurrence tumor tissue after radiotherapy of nasopharyngeal carcinoma. Results Tumor weighs of F1 and S1 transplanted tumors after irradiation were lower than those of tumors without irradiation(P<0.05).Each group had not pulmonary metastasis.After radiation，the rate of lymph node metastasis of S1 transplanted tumors was higher than that of F1 group but no significance(P>0.05).The expression of PCNA in F1 transplanted tumors was higher than that in S1 transplanted tumors(P<0.05)，while CK and PCNA expressed in S1 transplanted tumors were increased than those in F1 transplanted tumors(P<0.05).The expression of PCNA in recurrent NPC after radiotherapy was higher than that in NPC(P<0.05).Spearman correlation analysis showed the positive correlation between the expression of CK and Tubulin-β，also Tubulin-β and PCNA;as well as the expression of CK had positive correlation with Tubulin-β and PCNA in recurrent NPC(P<0.05).The expression of CK，Tubulin-β and PCNA were not related with age，sex，cervical lymph nody metastasis and clinical stage in both NPC and recurrent NPC group. Conclusion CK and Tubulin-β participated in the process of NPC post-radiotherapy recurrence through connection with cell proliferation，but couldn't be independent predictors of NPC recurrence.