Department of Pathology, The Johns Hopkins Hospital, Baltimore, Maryland 21287, USA.
Cancer Cytopathol. 2010 Dec 25;118(6):441-9. doi: 10.1002/cncy.20108. Epub 2010 Sep 9.
New developments in the treatment of lung cancer have necessitated the further histologic and cytologic subtyping of nonsmall cell lung carcinomas. Thyroid transcription factor-1 (TTF-1) long has served as the predominant marker for demonstrating lung origin. However, it is also expressed in a variety of other tumors, particularly neuroendocrine neoplasms and, to a much lesser degree, squamous cell carcinoma of the lung. Napsin-A, which is expressed in lung tissue, is a relatively new marker for lung adenocarcinoma. In this study, the authors examined the utility of napsin-A compared with TTF-1 in cytologic specimens of primary and metastatic, poorly differentiated lung adenocarcinomas.
The archives of the Department of Pathology at The Johns Hopkins Hospital were searched for cytologic cases of poorly differentiated lung adenocarcinoma that were histologically confirmed. In total, 75 patients (cases) along with 95 controls were included, each of whom had adequate cell block material for TTF-1 and napsin-A staining. Tissue microarrays of lung adenocarcinoma also were examined.
TTF-1 and napsin-A were detected in 61 of 75 cases (81.3%) and in 49 of 75 cases (65.3%), respectively. The sensitivity and specificity of TTF-1 were 81% each; and napsin-A had a greater specificity of 96%, and sensitivity of 65%. Napsin-A was not detected in small cell carcinomas or in other carcinomas of nonlung origin except for renal cell carcinoma.
Although TTF-1 had a higher sensitivity, napsin-A was useful as a surrogate marker when encountering a poorly differentiated lung adenocarcinoma or an unknown primary tumor, particularly in cytologic specimens and difficult cases. The current results indicate that the dual use of both markers may be necessary to improve diagnostic accuracy.
肺癌治疗的新进展需要进一步对非小细胞肺癌进行组织学和细胞学亚型分类。甲状腺转录因子-1（TTF-1）长期以来一直是证明肺来源的主要标志物。然而，它也在多种其他肿瘤中表达，特别是神经内分泌肿瘤，并且在较小程度上在肺鳞状细胞癌中表达。在肺组织中表达的 Napsin-A 是肺腺癌的一个相对较新的标志物。在这项研究中，作者研究了 Napsin-A 与 TTF-1 在原发性和转移性、低分化肺腺癌细胞学标本中的应用。
检索约翰霍普金斯医院病理科的细胞学病例，这些病例为低分化肺腺癌，经组织学证实。共纳入 75 例患者（病例）和 95 例对照，每位患者均有足够的细胞块材料进行 TTF-1 和 Napsin-A 染色。还检查了肺腺癌的组织微阵列。
在 75 例病例中的 61 例（81.3%）和 75 例病例中的 49 例（65.3%）中检测到 TTF-1 和 Napsin-A。TTF-1 的敏感性和特异性分别为 81%；Napsin-A 的特异性为 96%，敏感性为 65%。Napsin-A 未在小细胞癌或其他非肺来源的癌中检测到，除了肾细胞癌。
虽然 TTF-1 的敏感性更高，但在遇到低分化肺腺癌或未知原发性肿瘤时，Napsin-A 作为替代标志物很有用，特别是在细胞学标本和疑难病例中。目前的结果表明，同时使用这两种标志物可能有助于提高诊断准确性。
