@techreport{oai:kanazawa-u.repo.nii.ac.jp:00034886,
 month = {Dec},
 note = {本研究は癌抑制遺伝子p53と、DCCがそれぞれ存在する染色体17,18の数的異常を胃癌組織切片上で検索し、それぞれの染色体の2倍体から多倍体あるいはモノソミへの変化を検討し、同時にPCR-LOH法を用いてp53及びDCCのallelic lossを検出し数的異常との関係を解明することを目的とした。 まず、凍結切片とホルマリン固定パラフィン包埋切片を用いたin situ hybridizationの比較を行ったところ後者の方ですぐれた結果を得られた為、以下の研究は凍結切片のかわりにホルマリン固定パラフィン包埋切片を用いて行った。ビオチン標識プローブを蛍光色素とペロキシダーゼ反応で検出する方法を比較検討したところ、前者の方が染色体数の計測が容易であった。またジゴキシゲニン標識に比べ、ビオチン標識の方が良好な結果が得られた。 染色体の数的異常とallelic imbalanceの比較では17、番染色体にallelic imbalanceのみられた33例、18番染色体にallelic imbalanceのみられた20例についてFISHを行いそれぞれ28例、18例で良好な結果が得られた。17番染色体のpolysomyは14例にみられた9例がpolyclonalであった。18番染色体のmonosomyは2例、polyclonalは7例でmonsomyは2例にみられ、これらの症例では同染色体上の遺伝子は必然的にallelic lossを呈すると考えられる。またpolysomyの症例のうちtrisomyでは必然的に50%のallelic imbalanceを呈すると考えられ、PCR-LOHでみられる。allelic imbalanceは必ずしも遺伝子の選択的な物理的欠質を意味しない。A llelic imbalanceの解析には遺伝子に特異的なプローブを用いたFISH法によりcopy数を直接する事が必要と考えられる。, This study was designed to facilitate understanding of the process of gastric cancer progression by clarifying numerical changes of chromosomes 17 and 18 on gastric cancer sections. For DNA hybridization, we chose two chromosome-specific alpha-centromeric probes : one for chromosome 17 on whose short arm, tumor suppressor gene p53 located and the other for chromosome 18 on whose long arm tumor suppressor gene DCC located. In addition, to know the relationship between the numerical changes of these chromosomes and allelic loss of p53 and DCC,PCR-LOH was done using microsatelite polymorphism located at or linked to these genes.
In order to dissolve technical problems, we first compared the results of hybridization done by using frozen sections, and by formalin-fixed paraffin-embedded sections. We confirmed that the hybridization was not less efficient when formalin-fixed paraffin-embedded tissues were used than when frozen sections were used. Second, we compared two detection methods, i.e ., fluorescence detection and peroxidase detection. By the former method, the specimen had disadvantage of fading of fluorescences, however because virtually no background staining, the enumeration was easier than when peroxidase detection was applied. Thus finally we chose fluorescence in situ hybridization (FISH) on formalin-fixed paraffin-embedded section as the regular detection tmethod.
The 33 tumors which had allelic imbalance of p53 by PCR-LOH,and 20 tumors which had allelic imbalance of DCC were examined by FISH for numerical aberrations of chromosomes 17 and 18, respectively. FISH for chromosome 17 was successful in 28 tumors and for chromosome 18 in 18 tumors. Polysomy 17 was found in 14 and polysomy 18 in 7. No monosomy 17 was found, however monosomy 18 was found in 2 tumors. By PCR-LOH,the distinction of allelic imbalance due to numerical aberrations from those due to the selective physical deletion of genetic loci was impossible, although it is easy to detect numerical chromosomal aberrations by FISH.In this study it is shown that FISH is a useful tool to clarify chromosomal changes on formalin-fixed paraffin-embedded specimen., 研究課題/領域番号:07670196, 研究期間(年度)1995–1996, 出典：「胃癌凍結切片を用いた17番及び18番染色体の数的異常の解析」研究成果報告書　課題番号07670196
  (KAKEN：科学研究費助成事業データベース（国立情報学研究所）)
　　　本文データは著者版報告書より作成},
 title = {胃癌凍結切片を用いた17番及び18番染色体の数的異常の解析},
 year = {1997}
}