Expression Of Transcript Factor LHX2 In Esophageal Squamous Cell Carcinoma And Its Clinical Significance

In recent years,the incidence of esophageal carcinoma(EC)remains continuously increasing in the world.However,becasuse most patients are diagnosed at the stage of progress,therapeutic efficacy is dramatically poor.EC displays the difference of markedly geographical distribution In Asia,ESCC(esophageal squamous cell carcinoma)accounts for 90%of all EC patients,whereas in the US,ESCC accounts for only 26%of all EC patients.At present,the treatments of ESCC patients include surgery,chemotherapy and radiotherapy.But the survival rate and therapeutic effect of advanced ESCC are still elusive,so it is very imperative to seek for new targets for the therapy of ESCC patients.The LIM homeobox gene 2(LIM-homeobox gene 2,LHX2)belongs to the LIM homeobox gene family,which was identified due to its homeobox domain and LIM domain with rich cysteine.LHX2 is adjacent to c-Abl,and located in chromosome 9.The abnormal expression of LHX2 often results in chromosomal translocation.LIM homeobox family genes are implicated in a plethora of important physiological processes,such as cell division,cell proliferation,specific cell type differentiation,embryo development,etc.In addition to its specific physiological functions,LHX2 is also closely related to the occurrence and development of various kinds of tumors,such as LHX2 promotes the proliferation and metastasis of breast cancer by inducing PDGF-B signaling.In addition,LHX2 is highly expressed in a variety of human cancers,including gastric cancer,germ cell tumors,renal cell carcinoma,skin cancer,soft tissue tumors,muscle tumors,pancreatic cancer and glioma.Therefore,it is very essential to clarify the expression of LHX2 in ESCC.However,so far,the role of LHX2 in the occurrence and development of ESCC remains unclear.Therefore,in this study,immunohistochemistry,real-time quantitative PCR,Western blot and in situ hybridization technologies were exploited to detect the expressions of LHX2 in ESCC tissues and normal esophageal tissues,and its association of its expression with clinicopathlogical features was investigated.The current study will lay the foundation for seeking for new prognostic indicators of ESCC patients.Methods(1)Immunohistochemistry was used to analyze the expression of LHX2 protein in 91 cases of ESCC tissues and paired normal esophageal mucosa tissues.(2)Western blot was employed to investigate the expression of LHX2 protein in randomly selected 4 cases of ESCC tissues and corresponding normal esophageal tissues.(3)Real-time quantitative PCR was utilized to examine the expression of LHX2mRNA in randomly selected 4 cases of ESCC tissues and corresponding normal esophageal tissues.(4)In situ hybridization was used to analyze the expression of LHX2 mRNA in91 cases of ESCC tissues and paired normal esophageal mucosa tissues.(5)Statistical analysis:All data were investigated using SPSS21.0 software.t-test was used for comparison between two groups.The results of immunohistochemistry were analyzed by?2 test.The relationship between LHX2protein expression and prognosis of ESCC patients was analyzed by Log-rank test.A P value<0.05 was considered as statistical significance,and the results are expressed as the mean±SE.Results(1)The positive expression of LHX2 protein is mainly localized in the nucleus of ESCC.Positive expression rate of LHX2 protein in ESCC tissues(50/91,54.9%)was significantly higher than that in normal esophageal tissues(25/91,27.5%),and significant statistical difference were found between two groups(?~2=14.174,P<0.05).(2)Expression of LHX2 protein was closely correlated with histological grade(?~2=26.269,P=0.000),clinic staging(?~2=12.437,P=0.000),invasive depth(?~2=17.899,P=0.000)and lymph node metastasis(?~2=26.517,P=0.000),but not related to age(?~2=1.239,P=0.266)and gender(?~2=0.670,P=0.413)in ESCC patients.(3)Relative level of LHX2 protein expression in randomly selected 4 case of ESCC tissues was markedly higher than that in paired normol esophageal epithelial tissues,and there was statistical difference(P<0.05).(4)Relative level of LHX2 mRNA expression in randomly selected 4 case of ESCC tissues was evidently higher than that in paired normol esophageal epithelial tissues,and there was statistical difference(P<0.05).(5)The positive expression of LHX2 mRNA is mainly localized in the cytoplasm of ESCC.Positive expression rate of LHX2 mRNA in ESCC tissues was(46/91,50.5%)was dramatically higher than that in normal esophageal tissues(19/91,20.9%),and significant statistical difference were found between two groups(?~2=17.446,P<0.05).(6)Expression of LHX2 mRNA was tightly correlated with histological grade(?~2=7.638,P=0.022),clinic staging(?~2=7.041,P=0.008),invasive depth(?~2=16.091,P=0.000)and lymph node metastasis(?~2=14.694,P=0.000),but not related to age(?~2=0.932,P=0.334)and gender(?~2=1.023,P=0.312)in ESCC patients.(7)There was positive correlation between the expression of LHX2 mRNA and protein(P<0.05).(8)The result of Log-rank(Mantel-Cox)revealed that survival ratio of ESCC patients with low LHX2 expression was markedly higher than that with high LHX2expression,and the difference was statistical significance(P=0.011)ConclusionThe overexpressions of LHX2 protein and mRNA are exhibited in ESCC tissues,suggesting LHX2 may be related to occurrence,development and prognosis of ESSC.