中文摘要：

目的 检测成釉细胞瘤中是否存在成釉蛋白（AMBN）基因的异常。方法 收集10例成釉细胞瘤和1例成釉细胞癌的新鲜组织标本及相应外周血或牙龈黏膜组织，直接测序法分析AMBN基因；同时采用限制性片段长度多态性分析（RFLP）验证AMBN基因突变。结果 所有11例肿瘤中均未检测到AMBN基因突变，在9例肿瘤中发现的7种序列改变均为AMBN基因的多态性，其中3种为尚未报道的新位点。这3种多态性的基因型和等位基因型频率在健康人中的分布符合遗传平衡定律（Hardy—Weinberg平衡），且在肿瘤患者和健康人中的发生频率差异无统计学意义（P〉0．05）。结论 本组成釉细胞瘤中未发现AMBN基因突变，所发现的AMBN序列改变均属多态性，且与肿瘤发生并无明确关系。

英文摘要：

Objective To investigate the presence of mutation or polymorphism of ameloblastin （AMBN） gene in ameloblastomas. Methods Genomic DNA was extracted from frozen tissues of 10 ameloblastomas and one malignant ameloblastoma. AMBN gene alterations were detected by PCR-direct sequencing. Restriction fragment length polymorphism （RFLP） analysis was used to further determine the nature of the changes in AMBN detected in tumor samples in comparison to 100 control samples. Results AMBN mutation was not identified in all 11 tumor samples. The 7 types of AMBN gene alteration identified in 9 cases were proven to be polymorphisms, three of which were not previously reported. The frequency of genotype and allele of the three SNPs complied with the Hardy-Weinberg equilibrium. Neither genotype nor allele frequency showed a significant association with ameloblastoms. Conclusions AMBN gene mutation is not identified in the present group of ameloblastomas. The frequently detected AMBN alterations in ameloblastomas are polymorphisms, which appear to be unrelated to the occurrence of ameloblastomas.