| ObjeciveLaryngocarcinoma is the most common malignant tumor in otorhinolaryngological department.The morbidity of male is ten times more than female.In late years,the invasion of laryngocarcinoma trend heighten obviously,that threatened the life safety of human race seriously.Therefore,diagnosis laryngocarcinoma at early stage,predict the ability of trusion and transfer of laryngocarcinoma,increase the effectiveness of the treatment on laryngocarcinoma are all important.The same as other tumour,the occurrence and development of squamous carcinoma of larynx are a complex process with multiple gene participating in.RUNX3 gene are known as a early found tumor suppressor gene which is located in chromosome lp36.1.The lower expression of RUNX3 gene are closely connected with the occurrence and development of multiple malignant tumor.RUNX3 gene is an important link of TGF-βconduction path,which participate in the negative regulation and control of TGF-βepithelial cell growth.The methylation of DNA maybe the important mechanism of RUNX3 gene devitalization.RNUX3 gene 's devitalization because of methylation and allele gene deletion,which promoted the tumor's occurrence and development.Now we know that the status of methylation of RUNX3 gene in gastric cancer and peficancerous tissues,might be molecule marked object for early diagnosis of gastric cancer.Research indicate that the expressive deletion or down regulation of RUNX3 gene are found in gullet squamous carcinoma,lung cancer,liver cell carcinoma,colorectal cancer etc.But there are still not report about the methylation of RUNX3 gene in laryngocarcinoma research.We test the status of methylation in laryngocarcinoma tissues and it's opposite peficancerous tissues by means of Methylation specific PCR technology,do statistic analysis,and seek a new way for laryngocarcinoma's diagnosis and treatment at early stage. Methods40 Samples were taken in sheng jing hospital of china medical university during 2005 to 2008,Fresh samples were obtained from each patient at the time of surgery. The samples were immediately frozen in liquid nitrogen and were stored at-80℃,at the same time,get contrast tissues at more than 1cm distant from the tumor.The samples' age are from 34 to 79,average age is 60,including 36 males,4 females.12 with lymph node metastasis.All samples have been confirmed by post-op pathology.RT-PCR and PCR(Methylation specific PCR,MSP)technique were used to assess the status of methylation of promoter RUNX3 gene and the mRNA expression of 40 laryngocarcinoma tissues and its 29 opposite peficancerous tissues that 2cm distant from the tumor.Statistical analysis was performed using SPSS for window 13.0 software.The comparisons of means were carried out by analysis of variance.The comparisons of rates were carried out by X~2 test or fisher' exact probabilities.ResultsThe average gray-scale value of the Runx3 gene's expression mRNA detected in 40 laryngeal carcinoma was 1.6215±1.00640,which was lower than that in adjacent tissues samples5.6617±2.07458,(P＜0.05).The difference between two groups had statistics meaning.RUNX3 gene mRNA's lower expression is related with pathological differentiation degree in laryngocarcinoma samples.In laryngocarcinoma samples,The average gray-scale value of the Runx3 gene's expression mRNA in lower differentiation group is 0.7733±0.64691,which was lower than that in lower differentiation group 2.3155±0.64892,(P＜0.05).The difference between two groups had statistics meaning.RUNX3 gene mRNA's lower expression is related with regional lymph node metastasis in laryngocarcinoma samples.In laryngocarcinoma samples,The average gray-scale value of the Runx3 gene's expression mRNA in regional lymph node metastasis group is 0.6242±0.80444,which was lower than that in non-regional lymph node metastasis group 2.0489±0.7535,(P＜0.05).The difference between two groups had statistics meaning. In methylation result of laryngocarcinoma tissues and adjacent tissues,we found that no methylation of Runx3 promoter was found in adjacent tissues samples.But there was 38 methylation cases in 40 laryngeal carcinoma specimens.The rate of methylation of Runx3 pomoter in laryngeal carcinoma was higher than that in adjacent tissues(p＜0.05).The difference between two groups had statistics meaning.The Runx3 mRNA were down-regulated in lymphnode metastasis or poorly differentiated groups,but the Runx3 promoter methylation were detected in those groups markedly.Conclusions1,Ggen promoter hypermethylation was one of prime reasons which induced Runx3 gene inactivation in squamous carcinoma of larynx.RUNX3 promotor transcription initiation site may be the crucial locus of methylation of RUNX3 gene.2,In squamous carcinoma of larynx,RUNX3 gene mRNA espression reduce maybe closely related with the pathologic low differentiation of laryngocarcinoma.3,In squamous carcinoma of larynx,RUNX3 gene mRNA espression reduce maybe closely related with the regional lymph node metastasis.
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