眼睛翳狀贅肉中人類乳突病毒感染與p53不活化之研究

研究目的： 最近研究結果指出，患有翳狀贅肉的個案其組織偵測到腫瘤抑制基因p53基因突變，以及p53蛋白異常表現。人類乳突病毒 (Human papillomavirus, HPV) 16與18之病毒株E6蛋白使p53不活化，在子宮頸癌致癌機轉上扮演重要的角色。本研究進一步推論翳狀贅肉致病機轉中，造成p53蛋白不活化可能與人類乳突病毒感染有關。為探究人類乳突病毒16/18病毒株的E6蛋白不活化p53蛋白在翳狀贅肉的發生所扮演的角色，本研究將就病患檢體中人類乳突病毒16或18型的感染情況、人類乳突病毒E6致癌蛋白與p53蛋白表現等彼此之間的相關性做進一步分析。研究材料與方法： 本研究利用巢疊式聚合脢連鎖反應(nested-PCR)分析自129例罹患翳狀贅肉之翳狀贅肉組織及20例正常無翳狀贅肉的結膜組織檢體中，是否有人類乳突病毒16及18型的感染，並利用直接定序的方式檢測p53基因是否發生突變，此外亦以免疫組織化學染色法偵測p53蛋白與人類乳突病毒E6蛋白。實驗結果： 129位罹患翳狀贅肉的個案中，31名個案檢體中， 可偵測到人類乳突病毒 16/18 的感染，約佔24% (31 of 129)，而正常的20名受測檢體中則無檢出病毒核酸。經由免疫組織化學染色法偵測此31名人類乳突病毒16/18 DNA為陽性的翳狀贅肉的個案檢體中，有15名個案的檢體中可偵測出E6致癌蛋白，約佔48.3% (15 of 31)。另外，在罹患翳狀贅肉的個案中，其p53蛋白表現呈現陰性，與人類乳突病毒16/18 E6致癌蛋白呈現陽性有相關聯，但與p53基因突變的情形無關。結論： 人類乳突病毒16/18 E6致癌蛋白可在人類乳突病毒 DNA檢測呈現陽性的翳狀贅肉檢體中被偵測出，使p53基因不活化，參與人類乳突病毒感染翳狀贅肉的致病機轉。

Background: Our recent report indicated that tumor suppressor gene ( p53) mutations and protein aberrant expression were detected in pterygium. Inactivation of p53 by Human papillomavirus (HPV) 16/18 E6 plays a crucial role in cervical tumorigenesis. In this study, we further speculate that p53 inactivation may be linked with HPV infection in pterygium pathogenesis. To investigate the involvement of HPV 16/18 E6 in p53 inactivation in pterygium, the association between HPV 16 or HPV 18 infection, the HPV E6 oncoprotein, and p53 protein expression were analyzed in this study.Methods: HPV 16/18 infection was detected by nested-polymerase chain reaction (nested-PCR), the p53 mutation was detected by direct sequencing, and the p53 and the HPV 16/18 E6 proteins were studied using immunohistochemistry on 129 pterygial specimens and 20 normal conjunctivas. Results: The HPV 16/18 were detected in 24% pterygium tissues (31 of 129) but not in the normal conjunctiva, and the HPV 16/18 E6 oncoprotein was detected in 48.3% of HPV 16/18 DNA- positive pterygium tissues (15 of 31). In addition, p53 protein negative expression in pterygium were correlated with HPV 16/18 E6 oncoprotein expression but not with a p53 gene mutation. Conclusions: HPV 16/18 E6 contributes to HPV-mediated pterygium pathogenesis as it is partly involved in p53 inactivation and is expressed in HPV DNA–positive pterygium.