to malignant transformation. Oral leukoplakia is a common premalignant lesion in oral mucosa and the incidence of cancer progression into SCC has been reported to be 0~43%. The genetic alterations of oncogenes, tumor suppressor genes and DNA repair genes occur during carcinogenesis. In order to evaluate the role of epithelial cells in the early stage of carcinogenesis, we analyzed the alterations of genetic heterogeneity in epithelial cells of oral leukoplakia samples, using Laser capture microdissection(LCM). The incidence rate of microsatellite instability(MSI) and loss of heterozygosity(LOH) were analysed from the DNA of epithelial cells from 16 leukoplakia samples using adjacent fibroblasts as a normal control. In this study, LOH was found in epithelial cells of all 16 cases of leukoplakias while MSI has been observed in 3 cases. Interestingly, the fibroblasts showed LOH and MSI in some cases, which was confirmed by DNA sequencing. Taken together, this study showed that leukoplakia has multiple genetic alterations in fibroblasts as well as in epithelial cells, suggesting that interaction between epithelial cells and fibroblasts might be involved in the early step of carcinogenesis.

I. 서론
 II. 재료 및 방법
  1. 연구 대상
  2. 연구 방법
 III. 연구 결과
  1. 연구 대상자의 임상적 특징
  2. 현미부수체 불안정성(MSI)과 이형접합성소실(LOH) 분석
  3. 상피 이형성의 유무에 따른 LOH 분석
 IV. 총괄 및 고찰
 V. 결론
 VI. 참고문헌

• 권정화(연세대학교 치과대학 구강종양연구소, 구강병리학교실) | Jeong Hwa Kwon
• 홍두표(연세대학교 치과대학 구강종양연구소, 구강병리학교실) | Du Pyo Hong
• 김기열(연세대학교 치과대학 구강종양연구소, 구강병리학교실) | Ki Yeol Kim
• 김형준(연세대학교 치과대학 구강악안면외과학교실) | Hyung Jun Kim
• 최영욱(한국전기연구원) | Young Wook Choi
• 유미현(남서울대학교 치위생학과) | Mi Heon Ryu
• 김진(연세대학교 치과대학 구강종양연구소, 구강병리학교실) | Jin Kim correspondence