毛母质瘤中β联蛋白的突变基因分析

Gene mutations ofβ-catenin in pilomatricoma

目的探讨β联蛋白的突变基因及其蛋白表达与毛母质瘤发生的关系。方法选取67例毛母质瘤的组织标本进行β联蛋白的免疫染色,提取基因组DNA,进行β联蛋白的PCR扩增及测序,用克隆、测序及限制性内切酶的方法证实突变的存在。结果毛母质瘤中嗜碱粒细胞β联蛋白免疫染色阳性率为81%(26/32),β联蛋白外显子3基因突变率为61%(14/23)。其突变均位于β联蛋白外显子3的磷酸化位点或邻近位点。结论β联蛋白的基因突变及其核阳性与毛母质瘤的发生有关。

Objective To explore the relationship of gene mutation and protein expression of β-catenin with tumorigenesis of pilomatricoma. Methods Sixty-seven specimens of pilomatricoma were examined for β -catenin expression by immunohistochemistry. Genomic DNA was extracted from 23 specimens positive for nuclear β-catenin and 4 negative for nuclear β-catenin, then amplified and sequenced. The gene mutation of β-catenin was confirmed by subcloning and restriction endonuclease assay. Results Of the 67 specimens, 49 were positive for β-catenin; basophilic cells were detected in 32 of the 49 positive specimens, among which, 81% （ 26/32 ） displayed nuclear staining of β-catenin in basophilic cells. Sequence analysis revealed a mutation rate of 61% （ 14/23 ） in exon 3 of β-catenin. The mutations were located at or adjacent to the phosphorylation sites in exon 3 of β-catenin. However, no mutations were detected in the 4 specimens negative for nuclear β-catenin. Conclusion The gene mutation and nuclear expression of β-catenin may contribute to the tumorigenesis of pilomatricoma.