Cheng P, Schmutte C, Cofer K F, Felix J C, Yu M C, Dubeau L
Department of Gynecologic Oncology, USC/Norris Comprehensive Cancer Center, University of Southern California School of Medicine, Los Angeles 90033-0800, USA.
Br J Cancer. 1997;75(3):396-402. doi: 10.1038/bjc.1997.64.
We compared global levels of DNA methylation as well as methylation of a specific locus (MyoD1) in ovarian cystadenomas, ovarian tumours of low malignant potential (LMP) and ovarian carcinomas to investigate the association between changes in DNA methylation and ovarian tumour development. As we realized that cystadenomas showed different methylation patterns from both LMP tumours and carcinomas, we verified their monoclonal origin as a means of confirming their true neoplastic nature. High-pressure liquid chromatographic (HPLC) analyses showed that global methylation levels in LMP tumours and carcinomas were 21% and 25% lower than in cystadenomas respectively (P = 0.0001 by one-way variance analysis). Changes in the methylation status of the MyoD1 locus were not seen in any of ten cystadenomas analysed but were present in five of ten LMP tumours and in five of ten carcinomas (P = 0.03). These findings suggest that alterations in DNA methylation are absent (or at least not as extensive) in ovarian cystadenomas, but are present in LMP tumours, the phenotypic features of which are intermediate between those of benign and malignant ovarian tumours. The results also emphasize the merit of distinguishing ovarian LMP tumours from cystadenomas, in spite of their similar clinical characteristics.
我们比较了卵巢囊腺瘤、低度恶性潜能（LMP）卵巢肿瘤和卵巢癌中DNA甲基化的整体水平以及特定基因座（MyoD1）的甲基化情况，以研究DNA甲基化变化与卵巢肿瘤发生之间的关联。由于我们意识到囊腺瘤与LMP肿瘤和癌表现出不同的甲基化模式，我们验证了它们的单克隆起源，以此确认其真正的肿瘤性质。高压液相色谱（HPLC）分析显示，LMP肿瘤和癌中的整体甲基化水平分别比囊腺瘤低21%和25%（单向方差分析，P = 0.0001）。在所分析的10个囊腺瘤中，未观察到MyoD1基因座甲基化状态的变化，但在10个LMP肿瘤中有5个以及10个癌中有5个出现了这种变化（P = 0.03）。这些发现表明，卵巢囊腺瘤中不存在（或至少不那么广泛）DNA甲基化改变，但LMP肿瘤中存在这种改变，其表型特征介于良性和恶性卵巢肿瘤之间。结果还强调了尽管卵巢LMP肿瘤与囊腺瘤具有相似的临床特征，但仍需将它们区分开来的重要性。
