Sun W, Sun Y, Zhu M, Wang Z, Zhang H, Xin Y, Jiang G, Guo X, Zhang Z, Liu Y
Department of Radiation Oncology, Fudan University Shanghai Cancer Center, Shanghai 200032, P.R. China.
Cancer Research Institute of Fudan University Shanghai Cancer Center, Shanghai 200032, P.R. China.
Oncol Rep. 2014 Mar;31(3):1466-72. doi: 10.3892/or.2013.2949. Epub 2013 Dec 30.
In the present study, we studied the relationship between plasma cell-free DNA and the effect of preoperative chemoradiotherapy in patients with rectal cancer. The concentration, KRAS mutation and O6-methylguanine-DNA methyltransferase (MGMT) promoter methylation status of cell-free DNA were measured by using polymerase chain reaction (PCR) analyses. The response to chemoradiotherapy was assessed using tumor regression grading (TRG) scores. The cell-free DNA concentrations in patients with rectal cancer (n=34) were significantly higher compared to healthy controls (n=10). The 400-base pair (bp) DNA concentration, 400-/100-bp DNA ratio decreased significantly after chemoradiotherapy in the good response group. The incidence of KRAS mutation decreased significantly after chemoradiotherapy in both good and poor response groups. Higher MGMT promoter methylation status at baseline DNA was associated with a better tumor response. Therefore, cell-free DNA detection may be useful in evaluating the effect of preoperative chemoradiotherapy in patients with rectal cancer.
在本研究中，我们研究了直肠癌患者血浆游离DNA与术前放化疗效果之间的关系。采用聚合酶链反应（PCR）分析测定游离DNA的浓度、KRAS突变及O6-甲基鸟嘌呤-DNA甲基转移酶（MGMT）启动子甲基化状态。使用肿瘤消退分级（TRG）评分评估放化疗反应。直肠癌患者（n = 34）的游离DNA浓度显著高于健康对照者（n = 10）。在反应良好组中，放化疗后400碱基对（bp）DNA浓度、400-/100-bp DNA比率显著降低。在反应良好组和反应不良组中，放化疗后KRAS突变发生率均显著降低。基线DNA时较高的MGMT启动子甲基化状态与较好的肿瘤反应相关。因此，游离DNA检测可能有助于评估直肠癌患者术前放化疗的效果。
