Abstract:

Objective
To investigate  the mRNA  expression levels of epidermal growth factor receptor (EGFR) and  leucine-rich repeats and immunoglobulin like domains 1 (LRIG1) in  peripheral blood  from the patients with non-small cell lung cancer（NSCLC）,and to analyze their possible associations with the clinicopathological  parameters of the patients  and provide basis for treatment of NSCLC.Methods The expression levels of EGFR and LRIG1 mRNA were detecteded in peripheral blood of 69 NSCLC patients  by quantitative real-time PCR method.The associations between the gene expression levels and the clinical   stage of tumor, age,gender,and survival time of the patients were analyzed.Results  Compared with normal people,the expression level of LRIGI mRNA in peripheral blood of NSCLC patients was decreased and that of EGFR was increased（P<0.001）.The expression levels of LRIG1 and EGFR mRNA were not associated with gender,age,and histology of the patients(P>0.01 )，but they  were correlated with the  survival time and clinical stage of tumor of the  patients(P<0.001).The Cox regression analysis results indicated that the  clinical   stage of tumor，the expression levels of LRIG1 and EGFR mRNA  were independent prognostic factors for the NSCLC patients.The later the clinical  stage was,the worse the  prognosis was (P= 0.028);the relative risk degree （RR） = 1.548,95% CI：1.074－2.283;the higher the LRIG1 expression was, the better the prognosis of patients was (P= 0.026),RR = 0.242,95%CI：0.069－0.843;the higher the expression of EGFR mRNA was,the worse the prognosis was(P= 0.027),RR = 3.732,95%CI：1.165－11.956.The survival time of the patients with high expression of LRIG1 mRNA  was longer than the patients with lower expression of LRIG1 mRNA (χ2 =56.560,P<0.001);the survival time of the patients with high expression of EGFR mRNA  was shorter than the patients with low expression of EGFR mRNA (χ2 =51.962,P<0.001).The expression levels of LRIG1 and EGFR mRNA in the blood sample of the same patient were negatively related (r=－0.307,P=0.016).Conclusion LRIG1 can affect the clinical stage and survival time of NSCLC patients by negatively regulating the expression of EGFR.LRIG1 may affect the curative effectiveness and prognosis of NSCLC patients by regulating the expression of EGFR.

Key words: cancer,non-small cell lung, quantitative real-time PCR, epidermal growth factor receptor, leucine-rich repeats and immunoglobulin like domains, survival time