细胞角蛋白基因13在喉鳞状细胞癌中缺失和表达的研究

为了探讨细胞角蛋白基因13（Cytokeratin13,CK13)在喉癌发生中的作用，在CK13基因内部及附近选择5个微卫星引物进行杂合性丢失（loss of heterozygosity,LOH)分析，于DNA水平间接检测72例喉鳞状细胞癌患者中该基因的缺失，应用Northern Blot检测16例喉鳞癌患者的配对肿瘤及癌旁正常组织中CK13基因的表达差异；同时应用CK13蛋白单克隆抗体对不同分化程度的喉鳞癌组织进行免疫组化染色。结果表明：5个STR位点均存在LOH，其中D17S1964E、D17S2092、D17S791、D17S1665及D17S808位点的LOH频率分别为18．03％、28．13％、27．42％、39．68％和34．85％，其中D17S1665位点的LOH频率最高，至少一个位点出现LOH的病例高达77．78％（56／72），杂合性丢失与临床分期、淋巴结转移无显著相关，但与肿瘤分化程度高低相关（P＜0．05）。Northern blot结果表明：16例喉鳞癌患者C13基因在正常组织中的表达比肿瘤组织显著增强，免疫组化结果也显示CK13蛋白在正常组织或高分化肿瘤中的表达明显高于低分化者，且存在显著差异（P＜0．01）。证实CK13基因可能在喉鳞状细胞癌的发生中具有重要作用，可能是一个新的抑癌基因。

Studies of the Deletion and Expression of Cytokeratin 13 Gene in Laryngeal Squamous Cell Carcinoma

In order to investigate the role of Cytokeratin 13( CK13 ) gene in laryngeal carcinogenesis, we detected the deletion of CK13 gene through LOH analysis indirectly at DNA level using 5 STR primers within and near CK13 gene in 72 cases of laryngeal squamous cell carcinoma, then detected the differential expression between 16 cases of paired normal and cancerous tissue by Northern blot, and performed immunohistochemistry using well characterized monoclonal antibody against CK13 in squamous cell carcinoma of different stages. We found that all of the microsatellite loci exist LOH, and the LOH frequencies were 18.03%? 28.13%? 27.42% ? 39.68% and 34.85% at D17S1964E, D17S2092, D17S791, D17S1665 and D17S808 respectively. The LOH+ cases accounted for 77.78% (56/72), and the frequencies of LOH were not related to the type of laryngeal carcinoma and the lymphoid metastasis; but significantly related to the differentiation, P < 0.05 . CK13 gene is expressed significantly higher in 16 cases of normal tissues than in paired cancerous tissues, and the immunostain revealed that CK13 was expressed in normal laryngeal squamous cell or high differentiation stage, and its expression decreased or disappeared in poor ones, P <0.01. CK13 gene might play an important role in the laryngeal carcinogenesis, acting as a novel tumor suppressor gene, and may be relevant to laryngeal squamous cell carcinoma diagnosis and prognosis. Further research will contribute to conform it.