Objective To investigate the expressions of phosphorylated collapsin response mediator protein 2(pCRMP2)and class Ⅲ β-tubulin protein(Ⅲ β tubulin)in elderly patients with stage Ⅲ/Ⅳ non-small cell lung cancer (NSCLC),and to evaluate the value of the expressions of pCRMP2 and Ⅲβ tubulin in predicting the chemotherapeutic sensitivity of taxol.Methods A total of 127 elderly patients with stage Ⅲ/Ⅳ NSCLC were recruited,and expression levels of pCRMP2 and Ⅲ β tubulin were detected by immunohistochemistry and Western blot.Based on the levels of pCRMP2 and Ⅲ β tubulin expression,all patients were divided into four groups,including group A(low expressions of both pCRMP2 and lβ tubulin),group B(high expressions of both pCRMP2 and Ⅲβ tubulin),group C(high expression of only pCRMP2)and group D(high expression of only Ⅲ β tubulin).All patients were assigned to receive two cycles of TP chemotherapy regimens and then evaluate the effect of chemotherapy.If chemotherapy was invalid,a second-line chemotherapy regimen was administered.Relationships of response rate,overall survival(OS)and time on tumor progression(TTP) with expression levels of pCRMP2 and Ⅲ β tubulin protein were assessed.Results Among 127 elderly patients,the high expression rate of pCRMP2 and Ⅲ β tubulin protein were 51.2％ (65 cases) and 47.2％ (60 cases),respectively.The Western blot result displayed that the high expressions of pCRMP2 and Ⅲ β tubulin protein were significantly associated with pathologic stage,and with poorly differentiated adenocarcinoma(all P＜0.05).The pCRMP2 expression was also related to the clinical stage.Meanwhile,the overall survival rate(OS)was significantly lower in patients with high expression of pCRMP2 and Ⅲ β tubulin protein than in patients with low expression of the two proteins(P＜ 0.05).Expression of pCRMP2 and Ⅲβ tubulin protein was related with pathological grade and tissue classification.The remission rate (RR)was significantly higher in group A(65.3 ％)than in other three groups(RR in group C,group D and group B was 48.1％,44.0％,30.8％;all P＜0.05,respectively).There were significant differences in RR between group C,group D and group B(48.1 ％,44.0％,30.8％ respectively,P＜0.05).The OS of four groups were(510.5 ±20.9)d,(215.7±31.5)d,(326.9 ± 25.7)d,(298.7±21.2)d respectively.The OS was significantly longer in group A than in other groups(P ＜ 0.05).Conclusions The expression of pCRMP2 and Ⅲ β tubulin protein in NSCLC can be used to judge prognosis of lung cancer and to predict chemotherapy drug resistance.