두경부 편평세포암종과 양성 구강 상피성병소에서의 PTEN 발현 PTEN Expression in Head and Neck Squamous Cell Carcinomas and Benign Oral Epithelial Lesions
pp.253-262
The tumor suppressor gene, phosphate and tensin homologue(PTEN) has been shown to dephosphorylate the phosphatidylinositol 3-kinase(PI 3-K)-generated phosphatidylinositol(3-5)-triphosphate in vivo, thus interfering with the potentially oncogenic signals emanating from PI 3-K. Promoter hypermethylation of CpG islands has recently been shown to be an epigenetic change resulting in loss of function in some genes involved in cell cycle regulation and DNA repair. Immunohistochemal staining for monoclonal antibody 6H2.1 was performed from paraffin embedded blocks of 20 benign epithelial lesions and 40 head and neck squamous cell carcinomas(HNSCCs). Immunoreactivity was graded semiquantitatively by considering the percentage and intensity of the staining of the tumor cells. Also, this study tried to identify PTEN methylation in benign epithelial lesions(24 cases) and HNSCCs(44 cases of paraffin embedded blocks, 4 cases of frozen tissues) using methylation-specific PCR(MSP). In HNSCCs, immunoreactive scores of stage 1 and 2(12 cases, average score 85.2) were higher than those of stage 3 and 4(15 cases, 41.9) and statistically significant(P=0.017). Immunoreactive scores of moderate and poorly differentiated carcinomas(22 cases, 61.6) are more or less lower than those of well differentiated carcinoma(15 cases, 87.0) but not significant(P=0.361). Among 24 cases of benign epithelial lesions, 12 cases showed unmethylated PTEN but none methylated. In HNSCCs, 22 of 44 paraffin embedded blocks showed unmethylated PTEN but none methylated, and all 4 frozen tissue revealed unmethylated PTEN, one of which(25%) methylated. We consider that the loss of PTEN protein expression may be associated with the progression of HNSCCs and the other alteration rather than methylation may be important in the inactivation of PTEN in HNSCCs.
II. 재료 및 방법
1. 면역조직화학 염색
2. 파라핀-포매조직 및 동결조직에서의 DNA 추출
3. Methylation-specific PCR(MSP)를 이용한PTEN 메틸화 분석
4. 통계학적 처리
III. 연구결과
1. 임상 및 병리조직학적 소견
2. 양성 병소와 두경부 편평세포암종에서의 PTEN단백발현
3. 양성 병소와 두경부 편평세포암종에서의 PTEN메틸화 빈도
IV. 고찰
V. 결론
VI. 참고문헌