目的：探讨结直肠癌组织中长链非编码RNA母系印迹表达基因3（MEG3）的表达及其与肿瘤血管生成的关系。方法：用RT-PCR法检测42例结直肠癌患者癌组织与对应的癌旁组织标本，以及人结肠癌SW48细胞与人正常结肠NCM460细胞中MEG3表达，分析MEG3表达与患者临床病理因素的关系；免疫组化法检测上述组织标本中血管内皮生长因子（VEGF）的表达及血管密度，分析VEGF表达、血管密度与MEG3表达的相关性。结果：MEG3相对表达量在结直肠癌组织明显低于癌旁组织（0.12 vs. 1.00，P=0.003），在SW48细胞中明显低于NCM460细胞（0.15 vs. 1.00，P=0.007）；MEG3的相对表达量与患者肿瘤位置、浸润深度、分化程度和淋巴结转移无明显关系（均P>0.05）。结直肠癌组织中，VEGF表达与血管密度均明显高于癌旁组织（0.13 vs. 0.09；50.34 vs. 36.57，均P<0.05）；MEG3表达水平和VEGF表达水平及血管密度均呈负相关（r=-0.304、-0.342，均P<0.05）。VEGF是MEG3表达水平的独立影响因素（P=0.005）。结论：结直肠癌组织中MEG3表达降低，从而可能促进肿瘤组织VEGF表达量与血管生成。
Expression of maternally expressed gene 3 in colorectal cancer tissue and its relation with angiogenesis
Objective: To investigate the expression of the long non-coding RNA, maternally expressed gene 3 (MEG3), in colorectal cancer tissues and its relation with tumor angiogenesis. Methods: The MEG3 expressions in specimens of tumor tissues and their adjacent normal tissues from 42 colorectal cancer patients, as well as in human colon cancer SW48 cells and normal human colon NCM460 cells were determined by RT-PCR, and the relations of MEG3 expression with clinicopathologic factors of the patients were analyzed. The expression of vascular endothelial growth factor (VEGF) and vascular density in above specimens were measured by immunohistochemical staining, and the correlations of MEG3 expression with VEGF expression or vascular density were analyzed. Results: The relative MEG3 expression level in colorectal cancer tissue was significantly lower than that in adjacent normal tissue (0.12 vs. 1.00, P=0.003), and in SW48 cells was significantly lower than that in NCM460 cells (0.15 vs. 1.00, P=0.007), and the relative MEG3 expression level showed no significant relation with tumor location, depth of invasion, degree of differentiation and lymph node metastasis of the patients (all P>0.05). In colorectal cancer tissue, both VEGF expression and vascular density were higher than those in cancer adjacent normal tissue (0.13 vs. 0.09; 50.34 vs. 36.57, both P<0.05); the MEG3 expression level was negatively correlated with either the VEGF expression level or vascular density (r=–0.304; –0.342, both P<0.05). VEGF was an independent influential factor for MEG3 level (P=0.005). Conclusion: MEG3 expression is decreased in colorectal cancer tissue, which may probably facilitate VEGF expression and tumor angiogenesis.