Institute of Forensic Medicine and Laboratory Medicine, Jining Medical University, Forensic Science Center of Jining Medical University, Jining, Shandong, PR China.
Department of Pathology, Affiliated Hospital of Jining Medical University, Jining, Shandong, PR China.
Mol Genet Genomic Med. 2020 Apr;8(4):e1164. doi: 10.1002/mgg3.1164. Epub 2020 Feb 11.
Malignant tissue samples may be the only source of biological material for forensic investigations, including individual identification or paternity testing; however, such samples may lead to uncertainties due to frequent genomic aberrations associated with tumors, including alterations of the short tandem repeat (STR) loci used for forensic casework.
Short tandem repeat loci routinely used in forensic analysis (n = 23) were analyzed in 68 surgically removed papillary thyroid cancer specimens. Tumor cells and normal stromal cells were separated by laser capture microdissection.
Four kinds of changes were detected between normal and tumor tissues: partial loss of heterozygosity (pLOH), complete loss of heterozygosity, an additional allele, and a new allele not found in normal tissue. These changes were distributed across 20 of the tested STRs, with no mutations in VWA, D16S539, or Penta D. The most frequently affected locus was D2S1338, and the most frequent type of alteration was pLOH. Samples from patients aged 40-59 years exhibited the highest frequencies of STR variation.
Our results suggest that great care should be taken in the evaluation of DNA typing results obtained from malignant tissues, particularly when no normal tissue reference samples are available.
恶性组织样本可能是法医调查唯一的生物材料来源，包括个体识别或亲子鉴定；然而，由于肿瘤经常出现与基因组异常相关的情况，例如用于法医工作的短串联重复（STR）位点的改变，这些样本可能会导致不确定性。
在 68 个手术切除的甲状腺乳头状癌标本中分析了法医分析中常规使用的短串联重复位点（n=23）。通过激光捕获微切割将肿瘤细胞和正常基质细胞分离。
在正常组织和肿瘤组织之间检测到四种变化：部分杂合性丢失（pLOH）、完全杂合性丢失、额外的等位基因和在正常组织中未发现的新等位基因。这些变化分布在 20 个测试的 STR 中，VWA、D16S539 或 Penta D 没有突变。受影响最频繁的位点是 D2S1338，最常见的改变类型是 pLOH。40-59 岁患者的样本显示出最高的 STR 变异频率。
我们的结果表明，在评估从恶性组织中获得的 DNA 分型结果时应格外小心，特别是在没有正常组织参考样本的情况下。
