Abstract: OBJECTIVE:To investigate genomic alterations in STR loci on autosomal and sex chromosomes among human papillary thyroid cancers. METHODS: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: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.

Key words: microdissection, short tandem repeats, genetic alterations, papillary thyroid cancer