Immunohistochemical KIT (CD117) expression in thymic epithelial tumors
Immunohistochemical KIT (CD117) expression in thymic epithelial tumors
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DOI：
10.1378/chest.128.1.140
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发表时间：
2005-07-01
期刊：
影响因子：
9.6
通讯作者：
Tsuchiya, R
中科院分区：
文献类型：
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作者：
Nakagawa, K;Matsuno, Y;Tsuchiya, R
研究目的：胸腺上皮性肿瘤与前纵隔侵犯的原发性肺癌有时在临床和病理上很难鉴别。KIT（CD117）在胸腺上皮肿瘤的表达进行了研究，以评估其有用性作为一个标志物，支持鉴别诊断和选择therapy.Methods：我们研究了KIT的免疫组化表达在70切除胸腺上皮肿瘤（胸腺瘤，50胸腺癌，20）已重新分类的基础上，世界卫生组织的组织学分类系统。结果：50例胸腺瘤中仅有2例（4 20例胸腺癌中16例（80%）呈阳性反应。20例胸腺癌中有14例（70%）检测为CD5阳性。在肺鳞癌中，KIT和CD 5的免疫组化表达分别仅见于20例癌中的4例（20%）和3例（15%）。此外，在检查的40个样本中，（胸腺癌或肺癌）所有13例KIT和CD5均阳性的患者均为胸腺癌，16例KIT和CD5均阴性的患者中有13例为肺癌。KIT表达是胸腺癌诊断的一个有用的免疫组化标记，结合CD5免疫组化检测有助于胸腺癌与肺鳞癌的鉴别诊断。应鼓励在基因水平上进行进一步的研究，不仅要确定KIT在胸腺上皮肿瘤发生中的作用，而且要建立靶向治疗。
Study objectives: It is sometimes very difficult both clinically and pathologically to distinguish thymic epithelial tumors from primary lung carcinoma with massive anterior mediastinal involvement. The expression of KIT (CD117) in thymic epithelial tumors was investigated in order to evaluate its usefulness as a marker supporting differential diagnosis and choice of therapy.Methods: We examined the immunohistochemical expression of KIT in 70 resected thymic epithelial tumors (thymomas, 50; thymic carcinomas, 20) that had been reclassified on the basis of the World Health Organization histologic classification system. We also compared the expression of KIT and CD5 in 20 thymic carcinomas with their expression in 20 resected pulmonary squamous cell carcinomas that were spreading directly into the mediastinum.Results: Of the 50 thymomas, only 2 (4%) showed positive immunoreactivity for KIT (type A thymoma, 1; type B3 thymoma, 1), whereas 16 of the 20 thymic carcinomas (80%) showed positive immunoreactivity. Testing was positive for CD5 in 14 of the 20 thymic carcinomas (70%). In the pulmonary squamous cell carcinomas, in contrast, the immunohistochemical expression of KIT and CD5 was found in only 4 of 20 carcinomas (20%) and 3 of 20 carcinomas (15%), respectively. Furthermore, of the 40 specimens examined (either thymic or lung carcinoma) all 13 that were positive for both KIT and CD5 were thymic carcinomas, and 13 of the 16 that were negative for both were lung carcinomas.Conclusion: KIT expression is a useful immunohistochemical marker for the diagnosis of thymic carcinoma, and its examination in combination with CD5 immunohistochemistry would greatly help in the differential diagnosis of primary thymic carcinoma from pulmonary squamous cell carcinoma. Further investigations at a genetic level should be encouraged, not only to define the role of KIT in the oncogenesis of thymic epithelial tumors, but also to establish target-based therapy.