Background and objective: DNA methyltransferase 1 (DNMT1) is one of the important molecules regulating DNA methylation. The abnormal expression of DNMT1 was associated with the methylation and inactivation of tumor suppressor gene and tumorigenesis. The aim of this study is to clarify the difference of DNMT1 expression between lung cancer tissues and corresponding normal lung tissues, to analyze the relationships between DNMT1 expression and clinicopathologic characteristics of lung squamous cell carcinoma and adenocarcinoma, and to investigate the correlation between the expressions of DNMT1 and beta-catenin.
Methods: The expressions of DNMT1 and beta-catenin were examined in 84 lung squamous cell carcinoma and adenocarcinoma tissues and corresponding normal lung tissues using tissue microarray and immunohistochemistry.
Results: The average positive rate of DNMT1 was significantly higher in 84 lung cancer tissues [(58.04+/-35.07)%] than that in corresponding normal lung tissues [(6.88+/-10.26)%](t=12.835, P<0.001). The high expression of DNMT1 was positively correlated with adenocarcinoma histological type (r=0.365, P=0.001), poor differentiation (r=0.253, P=0.021) and lymph node metastasis (r=0.246, P=0.024) in lung cancer. The expression of DNMT1 was significantly correlated with the cytoplasmic expression of beta-catenin (r=0.571, P<0.001).
Conclusions: The high expression of DNMT1 was a common phenomenon in lung squamous cell carcinoma and adenocarcinoma. The high expression of DNMT1 was correlated with the malignant phynotype of lung cancer. DNMT1 may express coordinately with beta-catenin in lung cancer.
背景与目的: DNA甲基转移酶1(DNA methyltransferase 1, DNMT1)是调控DNA甲基化的重要分子之一，DNMT1的异常表达与抑癌基因的甲基化、失活和多种肿瘤的发生发展有关。本研究旨在分析阐明DNMT1在正常肺组织和肺癌组织中表达的差异及其与肺鳞癌和腺癌临床病理因素的关系，并探讨DNMT1与β-catenin在肺癌中表达的相关性。
方法: 采用组织芯片和免疫组化方法检测DNMT1和β-catenin在84例肺鳞癌、腺癌和相应癌旁正常肺组织中的表达情况。
结果: DNMT1在84例肺癌组织中的平均阳性率为(58.04±35.07) %，显著高于癌旁正常肺组织[(6.88±10.26) %](t=12.835, P＜0.001)。DNMT1的高表达与肺癌组织的腺癌组织学分型(r=0.365, P=0.001)、低分化程度(r=0.253, P=0.021)和淋巴结转移(r=0.246, P=0.024)正相关。DNMT1与β-catenin的细胞浆表达显著正相关(r=0.571, P＜0.001)。
结论: DNMT1的高表达是肺鳞癌和腺癌的普遍现象，DNMT1的高表达与肺癌的腺癌组织学类型和恶性表型有关；DNMT1在肺癌中可能与β-catenin协同表达。