Altered Expression And Clinical Significance Of Serum MALAT1 In Patients With Non-small Cell Lung Cancer Before And After Radiotherapy

Objective: The aim of this study was to prove that MALAT1 plays an important role in regulating radiosensitivity of non-small cell lung cancer in clinical practice.Meanwhile,it will lay the foundations for follow-up mechanism researches and help to find new targets of reversing the radiation resistance,which will bring new hope for related genes of targeting inhibition and will improve the therapeutic effect in cancer patients.Methods: Eligible patients were diagnosed clearly with non small cell lung cancer,were not treated with radiation before the diagnosis,and at least 50 Gy to the primary tumor was accepted after diagnosis.Setting up radiotherapy plans,then the serum levels of these patients were collected before and after radiotherapy,and RNA was extracted from the serum for PCR reactions.Results: There is no correlation between the different clinical features and the recent clinical efficacy of these 20 patients(P>0.05).The RNA from serum were extracted to reverse transcriptase,and the expression level of MALAT1 and GAPDH reference were tested by q PCR to get the amplification curves and the dissolving curves.The dissoluving curves of these two genes were single,indicating that the q PCR reaction had not nonspecific synthesis amplification,and the results had good specificity.The results of q PCR showed that the expression of MALAT1 was not related to the sex and age of the patients(P=0.2144、P=0.2000),the level of MALAT1 expression before radiotherapy was significantly higher in smoking patients than that of non smokers(P=0.0305).Classify patients according to the informations of the tumor,there was no correlation between the expression level of MALAT1 and the pathological type,anatomic classification,T stage,N stage and M stage of lung cancer(P=0.3951,P =0.8990,P =0.9896,P =0.7526,P =0.1280).The fold-change for MALAT1 expression level was calculated using ΔCt,which showed that the expression of MALAT1 was were enriched 2.306-fold relative to untreated radiotherapy(P=0.0349).Further analysis showed that the expression level of MALAT1 after radiotherapy had no significant difference between the high dose group(> 60Gy)and low dose group(≤60Gy)(P=0.7599).According to the curative efficacy,eligible patients were divided into effective group(CR+PR+SD)and ineffective group(PD),and results were shown that high expression level of MALAT1 before radiotherapy led to poor curative effects(P=0.0083).Conclusion: The high expression level of MALAT1 in patients with NSCLC predicts poor prognosis and is expected to be a sensitive indicator for predicting the efficacy of radiotherapy,it may be an important factor in the occurrence of radiation resistance.Meanwhile,smoking can increase the expression level of MALAT1 in patients with NSCLC and suggest a poor prognosis.