ABSTRACT
Objective To analyze the correlation between the ELL2 gene 1119 T>C polymorphism and the susceptibility to pleomorphic adenoma of the salivary gland.Methods The pedigree of the pleomorphic adenoma family of salivary gland was drawn.The exons of ELL2 gene in 5 members of salivary pleomorphic adenoma family were sequenced.A case-control study was conducted.One hundred and twelve patients with pleomorphic adenoma of the salivary gland who visited the Department of Oral and Maxillofacial Surgery of Shanxi Bethune Hospital from January 2016 to July 2020 were taken as case group,and 176 healthy examinees from January 2019 to January 2020 were taken as control group with age and sex as matching conditions.The 1119 T>C polymorphism of ELL2 genes in the two groups were detected with high resolution melting(HRM)curve.Chi-square test was adopted to analyze the correlation between gene polymorphism and the occurrence of pleomorphic adenoma of the salivary gland,stratified analysis was performed to evaluate the synergistic effect of smoking and genotype,and real time quantitative reverse transcription polymerase chain reaction(RT-PCR)was used to detect the expression level of ELL2 in individuals with different genotypes.Results The 1119 T>C polymorphism site existed in the exon 8 of ELL2 gene in a family with pleomorphic adenoma of salivary gland.The results of case-control study showed that the genotype frequency of homozygous CC was significantly higher in patients with pleomorphic adenoma of salivary gland than that in the controls(24.1%vs.11.9%,P=0.002).Homozygous CC was associated with increased risk for developing pleomorphic adenoma of salivary gland(OR=3.059,95%CI 1.494-6.263)in this cohort.Stratification analysis showed that smoking and 1119C allele cooperated to increase the risk of pleomorphic adenoma of salivary gland(OR=3.200,95%CI 1.460-7.014).The expression level of ELL2 mRNA in CC genotype was significantly higher than that in individuals with CT or TT genotype(P<0.05).Conclusion The genetic variation of ELL2 may play an important role in the occurrence of pleomorphic adenoma of salivary gland,and smoking combined with the 1119C allele increased the risk of this disease.