背景:结肠癌(CC)是一种异质性疾病,根据基因表达分为四种共有分子亚型(CMS)。局部CC(II/III期)患者缺乏预后因素,这使得分析可以描绘更具侵袭性的肿瘤的新分子标记变得至关重要。在上皮间质转化(EMT)等关键机制中必不可少的基因异常甲基化有助于CC中的肿瘤进展。Weevaluatethepresenceofhyper-andnowmethylationinsubrogateIHCmarkersusedforCMSclassification(CDX2,FRMD6,HTR2B,通过焦磷酸测序对144例II/III期患者和CC细胞系的ZEB1)。还通过定量PCR研究了对照和shRNA沉默的CC细胞系以及配对的正常组织/肿瘤中的ZEB1表达。还通过免疫组织化学在甲基化/未甲基化肿瘤中分析了ZEB1染色的模式。
结果:我们首次描述了在32.6%和50.9%的肿瘤中ZEB1基因的高甲基化和FRMD6基因的低甲基化,分别。此外,我们证实了甲基化细胞系中表观遗传药物的ZEB1再表达。ZEB1高甲基化在CMS1患者中更为常见,更重要的是,在我们的患者系列中,是与无病生存期(p=0.015)和总生存期(p=0.006)相关的良好预后因素,独立于其他重要的临床参数,如患者年龄,舞台,淋巴结受累,血管和神经周浸润.
结论:异常甲基化存在于用于CMS分类的代位基因中。我们的结果是ZEB1在CC中高甲基化的第一个证据,并且这种改变是预后良好的独立因素。
Colon cancer (CC) is a heterogeneous disease that is categorized into four Consensus Molecular Subtypes (
CMS) according to gene expression. Patients with loco-regional CC (stages II/III) lack prognostic factors, making it essential to analyze new molecular markers that can delineate more aggressive tumors. Aberrant methylation of genes that are essential in crucial mechanisms such as epithelial mesenchymal transition (EMT) contributes to tumor progression in CC. We evaluate the presence of hyper- and hypomethylation in subrogate IHC markers used for
CMS classification (CDX2, FRMD6, HTR2B, ZEB1) of 144 stage II/III patients and CC cell lines by pyrosequencing. ZEB1 expression was also studied in control and shRNA-silenced CC cell lines and in paired normal tissue/tumors by quantitative PCR. The pattern of ZEB1 staining was also analyzed in methylated/unmethylated tumors by immunohistochemistry.
We describe for the first time the hypermethylation of ZEB1 gene and the hypomethylation of the FRMD6 gene in 32.6% and 50.9% of tumors, respectively. Additionally, we confirm the ZEB1 re-expression by epigenetic drugs in methylated cell lines. ZEB1 hypermethylation was more frequent in CMS1 patients and, more importantly, was a good prognostic factor related to disease-free survival (p = 0.015) and overall survival (p = 0.006) in our patient series, independently of other significant clinical parameters such as patient age, stage, lymph node involvement, and blood vessel and perineural invasion.
Aberrant methylation is present in the subrogate genes used for
CMS classification. Our results are the first evidence that ZEB1 is hypermethylated in CC and that this alteration is an independent factor of good prognosis.