结肠癌p73基因D1S468位点遗传不稳定性及其与临床病理关系的研究

Genetic instability of D1S468 loci of p73 gene and its relationship with clinical pathological features in patients with colon cancers

目的检测结肠癌患者1号染色体D1S468位点的杂合性缺失（LOH）和微卫星不稳定（MIS），探讨p73基因遗传不稳定性在结肠癌发生发展中的作用，及其与结肠癌临床病理特点的关系。方法76例结肠癌患者的癌组织及周围正常组织取自石蜡包埋组织切片，苯酚-氯仿抽提法抽提DNA，聚合酶链反应-单链构象多态性分析（PCR-SSCP）扩增D1S468位点，放射自显影判断LOH和MIS。结果D1S468位点结肠癌组织的LOH、MIS检出率分别为45.3%、17.0%，均明显高于正常组织；LOH在结肠癌中的检出率与癌细胞的分化程度、Dukes分期、淋巴转移有关；MIS的检出率与肿瘤部位、组织分型、淋巴转移有关。结论LOH和MIS通过不同的途径调控原发性结肠癌的发生与发展。MIS多发生于结肠癌早期，可能与结肠癌的发生有关，而LOH可能促进了结肠癌淋巴的转移，参与了结肠癌的发展及恶化。

Objective To examine loss of heterozygosity （LOH）, microsatellite instability （MSI） of locus D1S468 on chromosome 1 and to identify the role of the genetic instability of p73 gene in the development of colon cancer and discuss the relationship between the genetic instability and the pathological features of colon cancer.Methods Tumors and paired normal tissues from 76 cases of colon cancers were obtained from formalin-fixed paraffin-embedded tissues. DNA was extracted by phenol-chloroform extraction. Polymerase chain reaction-single strand conformation polymorphism （PCR-SSCP） was performed to expand D1S468 loci of p73 gene. Autoradiography was used to investigate the genetic instability （LOH and MIS）. Results In this experiment, the frequency of LOH, MIS in 53 cases of colon cancer was 45.3% and 17.0% respectively, which was significantly higher than in normal tissue. The frequency of LOH in colon cancer was associated with the degrees of pathological differentiation, Dukes stages and lymph node metastasis. The frequency of MIS in colon cancer was associated with the site of the tumor, histological type of tumor, and lymph node metastasis.Conclusion MSI and LOH may regulate the development of colon carcinoma through different ways. MIS of colon cancer occur in the early stage mainly may be related to the occurrence of colon carcinoma and be expected to become the diagnostic molecular marker of early stage colon cancer. Meanwhile, LOH may participate in progression and worsening of cancer, and play the role of promoting lymph node metastasis.