| Summary: | 碩士 === 國立臺灣大學 === 法醫學研究所 === 97 === “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 biological 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) in paraffin and 100% in blood specimens, respectively. We revealed that 92 % (33/36) of 15 STR loci polymorphism in cancer tissues was perfectly matched with blood samples. The rest of 3 paraffin-embedded specimens DNA were 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 of different 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 might provide usefulness source of DNA analysis and forensic personal identification.
|
|---|
