Study On The CpG Island Hypermethylation And Expression Of HINT1Gene In The Tissues From Precancerous And Early Cancer Of Gastro-esophageal Junction

Objective:According to Siewert classification, gastroesophageal junctionadenocarcinoma can be divided into of distal esophagus adenocarcinoma,gastric cardia adenocarcinoma and proximal gastric cancer. DNA methylationimbalance is characteristic of tumorigenesis.HINT1genes in the plays animportant role in the channel Wnt/β-catenin,regulation of cellsurvival,proliferation and differentiation. Inactivation of the gene and proteinexpression decreased can activate pathway Wnt/β-catenin/TCF4,stimulate cellcycle regulatory proteins cyclinD1transcription,inhibition of apoptosis,therebypromote tumor development.The subject through studying astroesophageal junction precancerouslesions and early cancer’s HINT1CpG island methylation status and its proteinexpression,explore the relationship between HINT1gene methylation andgastroesophageal junction canceration tissues.Combined with its various riskfactors and similar or different molecular mechanisms,further explore theetiology and molecular differences between each group of diseases.Methods:Endoscopic tissues mainly from patients with endoscopeexamine and histopathology final diagnosis.Include31cases of Barrettesophageal (BE),6cases of esophageal high-grade intraepithelial neoplasiaand early cancer(EHIN and EEC),18cases of esophagealadenocarcinoma(EA);23cases of cardia low-grade intraepithelial neoplasia(CLIN),30cases of cardia high-grade intraepithelial neoplasia and earlycancer(CHIN and CEC),36cases of cardia adenocarcinoma(CA);14cases ofsubcardial gastric low-grade intraepithelial neoplasia (SGLIN),12cases ofsubcardial gastric high-grade intraepithelial neoplasia and early cancer(SGHINand SGEC),4cases of subcardial gastric adenocarcinoma(SGA);and normal group45cases.All biopsies was obtained by experienced endoscopistsendoscopic biopsy,Hp infection were detected by rapid urease test (RUT)detection.All biopsy specimens grouped according to pathological results.Allpatients’ age,sex,individual history about smoking and drinking, family historyof upper gastrointestinal cancer(UGIC),Hp infection were recorded.WithMethylation-specific PCR detected tissue gene methylation status.MeanwhileSP immunohistochemical method was used to detect the expression of HINT1genes in the respective organization.All data were analysised by SPSS13.0statistical software.We compared the relationship of every index with thechi-square test,paired chi-square test and Fisher’s exact test.Test level ofαequal to0.05.Results:1Gastroesophageal junction-related disease group HINT1promoter CpGisland methylation status analysis1.1The methylation rates of EHIN and EEC group,EA group,BE group andcontrol group were43.8%(7/16),50%(9/18),12.9%(4/31),0%(0/15) respectively.EHIN and EEC group compared with EA group,there was no statisticallysignificant differences(P=0.007,0.029);EHIN and EEC group compared withthe control,BE group,there were significant differences (P=0.007,0.029).Thereis no statistics significance between HINT1gene promoter methylation statusand age,family history, Hp infection history (P>0.05),but correlation withgender, smoking and alcohol consumption (P=0.039, P=0.009, P=0.006).1.2The methylation rates of CHIN and CEC,CA,CLIN and control tissuseswere53.3%(16/30),55.6%(20/36),34.8%(8/23),6.7%(1/15)respectively.Compared CHIN and CEC with CA,CLIN group,there was no statisticallysignificant (P=0.260);Compared CHIN and CEC with control groups,there wassignificant differences (P=0.002).There is no statistics significance betweenHINT1gene promoter methylation and age,gender,history of smoking,familyhistory,HP infection history (P>0.05).1.3The methylation rates of SGHIN and SGEC,SGA,SGLIN,control groupwere66.7%(8/12),75%(3/4),21.4%(3/14),6.7%(1/15) respectively.Compared SGHIN and SGEC group with SGLIN group, control group,there weresignificant difference (P=0.045, P=0.003);SGLIN group compared with controlgroup,there was no significant difference (P=0.330).There was no statisticssignificance between HINT1gene promoter methylation and age,gender,history of smoking,family history, HP infection history were not related (P>0.05).2Gastroesophageal junction-related disease group HINT1protein expressionstatus analysis2.1The protein expression rates of EHIN and EEC,EA,BE,control grouptissuses were25.0%(4/16),33.3%(6/18),61.3%(19/31),73.3%(11/15)respectively.Compared EHIN and EEC group with EA group,there was nostatistically significant (P=0.715);Compared EHIN and EEC group withcontrol group and BE group,There were significant differences(P=0.012,P=0.018);BE group compared with the normal group,there was nostatistically significant (P=0.421).2.2The protein expression rates of CHIN and CEC, CA, CLIN and controlwere23.1%(6/26),27.3%(6/22),60.9%(14/23),60.0%(9/15) respectively.Compared CHIN and CEC with control group, CLIN, there were significantdifferences (P=0.018, P=0.007); Compared CHIN and CEC with CA group,there was no statistically significant (P=0.738). CLGD group compared withcontrol group, there was no statistically significant (P=0.957).2.3The protein expression rates of SGHIN and SGEC,SGA,SGLIN,controltissuses were16.7%(2/12),50.0%(2/4),35.7%(5/14),73.3%(11/15) respectively.SGHIN and SGEC group compared with SGLIN group,there was nostatistically significant (P=0.391); SGHIN and SGEC group compared with thecontrol group,there were significant difference (P=0.006).SGLIN groupcompared with the control group,there was significant difference (P=0.042).3Correlation between HINT1gene promoter methylation and its proteinexpression3.165cases of cardiac precancerous and EA tissuses,the HINT1proteinexpression rate of HINT1gene promoter methylation positive and negative group was5%(1/20),62.2%(28/45) respectively.There was significantdifferences between the two comparison (P=0.000),There was significantlynegatively correlation between HINT1gene promoter methylation and itsprotein expression (R=-0.438,P=0.000).3.271cases of cardiac precancerous and CA tissuses,the HINT1proteinexpression rate of HINT1gene promoter methylation positive and negativegroup were17.1%(6/35),55.6%(20/36) respectively.There was significantdifferences between the two comparison (P=0.001).There were significantlynegatively correlated between HINT1gene promoter methylation and itsprotein expression (R=-0.362, P=0.002).3.330cases of subcardial gastric precancerous and SGA tissuses,the HINT1protein expression rate of HINT1gene promoter methylation positive andnegative group were14.3%(2/14),43.8%(7/16) respectively.There was nostatistically significant (P=0.118),There were no significant correlationbetween HINT1gene promoter methylation and its protein expression(R=-0.321, P=0.084).Conclusions:1HINT1gene promoter CpG island methylation rate significantlyincreased in esophageal high-grade intraepithelial neoplasia and early cancertissuses.HINT1protein expression significantly decreased.History of tobaccoand alcohol can significantly increase HINT1gene promoter CpG islandmethylation incidence in distal esophagus tumors (Siewert TypeⅠ).Tobacco,alcohol consumption plays an important role in the progression of esophagealadenocarcinoma.2HINT1gene promoter CpG island methylation rate significantlyincreased in cardia high-grade intraepithelial neoplasia and early cancer,cardialow-grade intraepithelial tissuses.HINT1promoter CpG island methylationmay be cardia tumors (Siewert Type Ⅱ) early events,HINT1methylation-positive patients with low-grade intraepithelial should bestrengthened clinical follow-up.3HINT1gene promoter CpG island methylation rate significantly increased in subcardial gastric precancerous and early cancer;HINT1proteinexpression significantly decreased.4There may be similar molecular mechanisms between three types ofgastroesophageal junction tumors with Siewert.5There were significantly negative correlation between HINT1promoterCpG islands hypermethylation and its protein expression.HINT1gene promotermethylation in a certain extent, affected the gene expression,leading to HINT1gene expression decline.+...