Department of Otorhinolaryngology, Head and Neck Surgery, Graduate School of Medicine, Chiba University, Chiba, Japan.
Department of Molecular Oncology, Graduate School of Medicine, Chiba University, Chiba, Japan.
Cancer Sci. 2020 Apr;111(4):1407-1416. doi: 10.1111/cas.14338. Epub 2020 Feb 27.
Irradiation, or chemoradiotherapy, is a curative treatment for oropharyngeal squamous cell carcinoma (OPSCC). Its invasiveness, however, can often negate its efficacy. Therefore, developing methods to predict which patients would benefit from irradiation is urgent. Promoter DNA hypermethylation was recently reported to correlate with favorable OPSCC prognosis. It is still unclear, however, whether there is an association between promoter DNA methylation and response to irradiation. In this study, we analyzed DNA methylation in the specimens from 40 OPSCC patients who had undergone irradiation, using the Infinium assay. Our results showed significant correlation between high levels of promoter DNA methylation and better response to treatment (P < 0.01). We used the 10 most differentially-methylated genes between responders and non-responders to develop a panel of predictive markers for efficacy. Our panel had high sensitivity, specificity and accuracy (92%, 93% and 93%, respectively). We conducted pyrosequencing to quantitatively validate the methylation levels of 8 of the 10 marker genes (ROBO1, ULK4P3, MYOD1, LBX1, CACNA1A, IRX4, DPYSL3 and ELAVL2) obtained by Infinium. The validation by pyrosequencing showed that these 8 genes had a high prediction performance for the training set of 40 specimens and for a validation set of 35 OPSCC specimens, showing 96% sensitivity, 89% specificity and 94% accuracy. Methylation of these markers correlated significantly with better progression-free and overall survival rates, regardless of human papillomavirus status. These results indicate that increased DNA methylation is associated with better responses to irradiation therapy and that DNA methylation can help establish efficacy prediction markers in OPSCC.
放疗或放化疗是治疗口咽鳞状细胞癌（OPSCC）的一种有治愈可能的方法。然而，其侵袭性往往会降低其疗效。因此，开发预测哪些患者将从放疗中受益的方法迫在眉睫。最近有研究报道，启动子 DNA 高甲基化与 OPSCC 的良好预后相关。然而，启动子 DNA 甲基化与对放疗的反应之间是否存在关联尚不清楚。在这项研究中，我们使用 Infinium 检测分析了 40 名接受放疗的 OPSCC 患者标本中的 DNA 甲基化。我们的结果表明，启动子 DNA 高甲基化水平与治疗反应良好之间存在显著相关性（P<0.01）。我们使用应答者和无应答者之间差异甲基化程度最高的 10 个基因开发了一个预测疗效的标志物面板。我们的标志物面板具有较高的敏感性、特异性和准确性（分别为 92%、93%和 93%）。我们进行了焦磷酸测序，以定量验证通过 Infinium 获得的 10 个标志物基因（ROBO1、ULK4P3、MYOD1、LBX1、CACNA1A、IRX4、DPYSL3 和 ELAVL2）中的 8 个基因的甲基化水平。焦磷酸测序验证显示，这 8 个基因在 40 个标本的训练集和 35 个 OPSCC 标本的验证集中具有较高的预测性能，对训练集标本的敏感性为 96%，特异性为 89%，准确性为 94%。这些标志物的甲基化与无进展生存期和总生存期的改善显著相关，与人类乳头瘤病毒状态无关。这些结果表明，DNA 甲基化增加与对放疗的更好反应相关，并且 DNA 甲基化有助于在 OPSCC 中建立疗效预测标志物。
