甲状腺乳头状癌组织常染色体和性染色体STR基因座变异分析

Mutational analysis of STR loci genomic changes in human papillary thyroid cancers

目的:探讨甲状腺乳头状癌组织中短串联重复序列(STR)基因座变异规律以及显微切割技术在肿瘤组织鉴定中的应用,为甲状腺乳头状癌组织的个体识别及亲缘关系鉴定提供依据.方法:收集43例人甲状腺乳头状癌和癌旁正常组织经激光显微切割获取肿瘤细胞和间质细胞,采用Chelex-100法提取DNA,分别采用Goldeneye■DNA 22NC、Goldeneye■DNA 27YB和Goldeneye■DNA 17X试剂盒进行常染色体和性染色体STR基因座PCR扩增,ABI 3500遗传分析仪检测进行STR分型.结果:甲状腺乳头状癌组织肿瘤间质细胞与对应癌旁组织的STR分型一致.43例癌组织的肿瘤细胞有9例STR基因座发生了变异,在常染色体和X染色体联合检测的37个STR基因座共检出11次变异(常染色体变异7次,X染色体变异4次),其中等位基因增加3次,部分杂合性丢失6次,出现新等位基因2次,并且同一甲状腺乳头状癌肿瘤细胞可同时发生多种变异.Y染色体STR基因座没有检出变异.结合实验结果与患者临床资料分析,STR基因座的变异与甲状腺乳头状癌患者的临床分期、性别无明显相关关系,与患者的年龄正相关,差异具有统计学意义(P<0.05).结论:甲状腺恶性肿瘤组织常染色体和X染色体STR基因座存在变异,而且变异更可能发生在年龄大的甲状腺乳头状癌组织中,在司法鉴定中进行STR分型时应谨慎判型.显微切割技术可准确分离间质细胞,是解决此类恶性肿瘤组织检材涉及的案件进行身源鉴定的有效手段.

OBJECTIVE: To investigate genomic alterations in STR loci on autosomal and sex chromosomes among human papillary thyroid cancers. METHODS丗 Tumor and stromal cells were separated from papillary thyroid cancer tissues from 43 unrelated patients using laser capture microdissection. DNA of tumor cells, stromal cells and adjacent normal tissues were extracted using Chelex-100, amplified using Goldeneye■ DNA 22NC, Goldeneye■ DNA 27YB and Goldeneye■ DNA 17X PCR amplification kit and analyzed using ABI 3500 Genetic Analyzer. RESULTS丗 The genotypes of stromal cells from different cancer tissues were consistent with that from corresponding adjacent normal tissues. Genomic alterations were detected in 11 out of 43 tumor cell specimens. Eleven alterations were detected on 37 STR loci within autosomal and X chromosomes,including additional alleles:3 times,partial loss of heterozygosity:6 times,and new alleles: 2 times. Moreover,the alternations might have occur simultaneously at more than one loci in the same tumor cells. There were no genomic alterations detected on STR loci of the Y chromosome. With respect to clinical data, there was no significant association between STR variations and staging of the cancers, nor patient's gender. However,there were significant differences between age of the patients and STR loci alterations (P< 0.05). CONCLUSION:There were genomic alterations in the STR loci among autosomal and sex chromosomes in human papillary thyroid cancer cells. In addition, these alterations occurred more often in older patients.Stromal cells could be separated accurately from tumor tissues by microdissection which would provide more opportunity for investigations.