癌症組織於血緣鑑定的可適用性之評估：以乳癌症患者癌變組織STR 15型之突變研究為例

自1991年STR發表於文獻後，STR式型別鑑驗技術隨即快速發展，確立許多適合供DNA鑑定的STR標記，隨之利用複合式PCR反應，可同步複製數個STR標記，這些選定的STR標記，對各種檢體，包括血液、唾液、肌肉、骨骼、毛髮、牙齒或腐敗檢體，所萃取之DNA經由複合式PCR反應，均可得到理想的鑑驗結果，並藉由增加STR標記的數目，提高識別率（power of discrimination）。STR標記除了運用於法醫刑事鑑識外，也被利用於分析骨髓移植成效、遺傳基因疾病、族群基因研究及腫瘤基因變異研究。實務上，許多社會上知名的DNA鑑定案例，因關係人已不在人世，亦或當臨床上，實驗室蠟塊組織切片混淆或是否組織遭錯置污染時，蠟塊組織便可能成為DNA鑑驗檢體，供血緣鑑定或鑑定組織的來源。臨床上病理切片的蠟塊組織，可能是發展至不同程度的病變組織，包括發炎、良性腫瘤及惡性腫瘤等，這些病變組織，特別是惡性腫瘤的組織，其一般DNA鑑定常規用的STR標記特性是否因其為良性增生或已經癌化而產生突變，以致影響鑑驗結果，值得探討。STR式型別鑑驗技術之所以能符合鑑定需求，除了高特異性、多型性、短片段容易複製之外，另一個特性為低突變率，許多研究顯示，一般DNA鑑定常用的STR標記其突變率約介於10^(-3)至10^(-4)之間，至於癌症組織的STR標記突變研究資料則相當有限。本研究希望藉由國人乳癌組織的基因突變探討，能提供日後DNA鑑定重要的參考依據。

關鍵字

乳癌；基因突變；石蠟包埋； STR式型別鑑驗

並列摘要

”Investigation” is the major work of Forensic Medicine. The forensic identification is not only restricted to realize the reason of death, but also involves a lot of judicial investigations, such as parentage analysis, paternity test or personal identification and material evidence examination. Most of the forensic evidence examination, for example, blood, sperm, sweat, skin, hair, nail and even teeth and bone, relies on DNA analysis technology. Short tandem repeat (STR) system is one of the main methodologies used in criminal investigation activities. Evidences have shown that DNA in paraffin-embedded tissues is relatively stable, and it is not difficult to extract DNA from paraffin-embedded tissues. Furthermore, it has been proved that cancer is induced by accumulation of genetic mutations. Thus, it is worthy to consider that if the paraffin-embedded cancer tissues could provide a model of forensic identification.In this study, we assayed 50 paraffin-embedded breast cancer tissues, which were collected from August 2007 to June 2008, and their counterpart blood specimens as control groups. The extraction rates of DNA were 72% (36/50) and 100% in paraffin and blood specimens, respectively. We revealed that 91% (33/36) of 15 STR loci polymorphism in cancer tissues was perfectly matched in blood samples. The rest of 3 paraffin-embedded specimens DNA was found to be mutated from control group, which the mutation rate was approximately 8% (3/36). In addition, we also discovered that these 3 tissues have the same single locus mutation. Using STR system to evaluate the parentage relationship, single locus mutation is not enough to exclude the possibility that the two specimens are from the identical source. More than two loci are needed. Thus, these results demonstrate that DNA in most of cancer tissues is not mutated from normal parts, indicating that in some circumstances, paraffin-embedded cancer tissues can provide usefulness source of DNA analysis and forensic person identification.

並列關鍵字

Breast cancer ； Paraffin-embedded DNA extraction ； Gene mutation ； 15 STR loci polymorphism

參考文獻

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癌症組織於血緣鑑定的可適用性之評估：以乳癌症患者癌變組織STR 15型之突變研究為例

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