食管鳞状细胞癌中CDKN2A（p14ARF和p16INK4a）基因的启动子高甲基化及定量表达分析

Promoter hypermethylation and quantitative expression analysis of CDKN2A (p14ARF and p16INK4a) gene in esophageal squamous cell carcinoma.

作者信息

Ito Shuhei, Ohga Takefumi, Saeki Hiroshi, Watanabe Masayuki, Kakeji Yoshihiro, Morita Masaru, Yamada Tomomi, Maehara Yoshihiko

机构信息

Department of Surgery and Science, Graduate School of Medical Sciences, Japan.

出版信息

Anticancer Res. 2007 Sep-Oct;27(5A):3345-53.

Abstract

BACKGROUND

Abnormal hypermethylation of the CDKN2A (p14ARF and p16INK4a) gene can lead to repression of gene expression and contribute to carcinogenesis and tumor progression.

MATERIALS AND METHODS

In esophageal squamous cell carcinoma (ESCC), the promoter methylation of the p14ARF and p16INK4a gene was investigated in 38 cases by methylation-specific PCR and the expression of each gene in 18 cases was quantified by real-time quantitative reverse transcription-PCR.

RESULTS

Aberrant methylation of p14ARF and of p16INK4a was detected in 23 (61%) and 29 (76%) cases, respectively. No relationship was found between clinicopathological variables and p14ARF or p161NK4a promoter methylation. A statistically significant association between p14ARF methylation status and mRNA expression was found (p=0.0441). Regarding p14ARF, a low expression group showed a significantly higher proportion of cases with deep invasion of tumor, lymph node metastasis, and a high TNM stage of disease (p=0.0474, 0.0474, and 0.0441, respectively), and a significantly poor prognosis (p=0.0402). Regarding p161NK4a, no relationship was found among the methylation status, mRNA expression and clinicopathological variables, including survival.

CONCLUSION

Our results suggest that methylation is the predominant mechanism of inactivation of the p14ARF gene in ESCC. The decrease in p14ARF gene expression associated with invasive and metastatic phenotypes may be significant as an indicator of the malignant potential of human ESCC.

摘要

背景

CDKN2A（p14ARF和p16INK4a）基因的异常高甲基化可导致基因表达受抑，并促进肿瘤发生和进展。

材料与方法

采用甲基化特异性PCR检测38例食管鳞状细胞癌（ESCC）中p14ARF和p16INK4a基因的启动子甲基化情况，运用实时定量逆转录PCR对18例中各基因的表达进行定量分析。

结果

分别在23例（61%）和29例（76%）中检测到p14ARF和p16INK4a的异常甲基化。未发现临床病理变量与p14ARF或p16INK4a启动子甲基化之间存在关联。发现p14ARF甲基化状态与mRNA表达之间存在统计学显著关联（p = 0.0441）。就p14ARF而言，低表达组肿瘤深层浸润、淋巴结转移及疾病TNM分期高的病例比例显著更高（分别为p = 0.0474、0.0474和0.0441），且预后显著较差（p = 0.0402）。就p16INK4a而言，未发现甲基化状态、mRNA表达与包括生存在内的临床病理变量之间存在关联。

结论

我们的结果表明，甲基化是ESCC中p14ARF基因失活的主要机制。与侵袭性和转移表型相关的p14ARF基因表达降低，作为人类ESCC恶性潜能的指标可能具有重要意义。