Cancer Molecular Pathology, School of Medicine and Menzies Health Institute Queensland, Griffith University, Queensland, Australia.
Department of Biochemistry and Molecular Biology, University of Rajshahi, Rajshahi, 6205, Bangladesh.
Genes Chromosomes Cancer. 2018 May;57(5):240-251. doi: 10.1002/gcc.22525. Epub 2018 Jan 30.
The present study aims to examine promoter methylation status of FAM134B in a large cohort of patients with colorectal adenocarcinomas. The clinical significances and correlations of FAM134B promoter methylation with its expression are also analysed. Methylation-specific high-resolution melt-curve analysis followed by sequencing was used to identify FAM134B promoter methylation in colorectal adenomas (N = 32), colorectal adenocarcinomas (N = 164), matched adjacent non-neoplastic colorectal mucosae (N = 83) and colon cancer cell lines (N = 4). FAM134B expression was studied by real-time quantitative polymerase chain reaction, immunohistochemistry, and Western blots. FAM134B promoter methylation was more frequent in adenocarcinomas (52%; 85/164) when compared to that of adenomas (28%; 9/32) and non-neoplastic mucosae (35%; 29/83). Cancer cells exhibited higher methylation when compared to non-neoplastic cells. FAM134B promoter methylation was inversely correlated with low FAM134B copy number and mRNA/protein expressions, whereas in-vitro demethylation has restored FAM134B expression in colon cancer cells. FAM134B promoter methylation was associated with high histological grade (P = .025), presence of peri-neural infiltration (P = .012), lymphovascular invasion (P = .021), lymph node metastasis (P = .0001), distant metastasis (P = .0001) and advanced pathological stages (P = .0001). In addition, FAM134B promoter methylation correlated with cancer recurrence and poor survival rates of patients with colorectal adenocarcinomas. To conclude, FAM134B promoter methylation plays a key role in regulating FAM134B expression in vitro and in vivo, which in turn contributes to the prediction of the biological aggressiveness of colorectal adenocarcinomas. Furthermore, FAM134B methylation might act as a marker in predicting clinical prognosis in patients with colorectal adenocarcinomas.
本研究旨在检测 FAM134B 在大量结直肠腺癌患者中的启动子甲基化状态。同时还分析了 FAM134B 启动子甲基化与其表达的临床意义及相关性。采用甲基化特异性高分辨率熔解曲线分析结合测序的方法，检测 32 例结直肠腺瘤、164 例结直肠腺癌、83 例配对的非肿瘤性结直肠黏膜和 4 例结肠癌细胞系中 FAM134B 启动子甲基化。采用实时定量聚合酶链反应、免疫组织化学和 Western blot 检测 FAM134B 表达。与腺瘤（28%，9/32）和非肿瘤性黏膜（35%，29/83）相比，腺癌中 FAM134B 启动子甲基化更为频繁（52%，85/164）。与非肿瘤细胞相比，癌细胞中存在更高的甲基化。FAM134B 启动子甲基化与低 FAM134B 拷贝数和 mRNA/蛋白表达呈负相关，而体外去甲基化可恢复结肠癌细胞中 FAM134B 的表达。FAM134B 启动子甲基化与高组织学分级（P=0.025）、神经周围浸润（P=0.012）、血管淋巴管浸润（P=0.021）、淋巴结转移（P=0.0001）、远处转移（P=0.0001）和晚期病理分期（P=0.0001）相关。此外，FAM134B 启动子甲基化与结直肠腺癌患者的癌症复发和不良生存率相关。总之，FAM134B 启动子甲基化在体外和体内调节 FAM134B 表达中起关键作用，进而有助于预测结直肠腺癌的生物学侵袭性。此外，FAM134B 甲基化可能作为结直肠腺癌患者预测临床预后的标志物。
