Shah Rajshri N, Badve Sunil, Papreddy Kashireddy, Schindler Susanne, Laskin William B, Yeldandi Anjana V
Department of Pathology, Northwestern University, Chicago, IL 60611, USA.
Hum Pathol. 2002 Sep;33(9):915-20. doi: 10.1053/hupa.2002.126876.
Mucinous bronchioloalveolar carcinomas (BACs) can closely mimic metastatic adenocarcinoma to the lung both clinically and morphologically. Several studies have demonstrated that the differential expression of cytokeratin 7 (CK7) and cytokeratin 20 (CK20) is a valuable diagnostic tool in differentiating primary pulmonary adenocarcinomas (PPAs) (usually CK7 positive/CK20 negative) from metastatic colonic adenocarcinoma (usually CK7 negative/CK20 positive). The present study is designed to correlate the histologic subtypes of PPA with expression of 7 and 20. A total of 113 cases of bonafide PPA were selected and classified according to the 1999 World Health Organization criteria as adenocarcinoma, NOS (n = 80), nonmucinous BAC (n = 14), and mucinous BAC (n = 19). Representive sections of all the tumors were immunohistochemically analyzed for CK7 and CK20 expression. To evaluate the diagnostic utility of CK7 and CK20 expression, 6 cases of colonic adenocarcinoma metastatic to the lung were tested with the same antibodies and compared with mucinous BAC. Results were expressed in a semiquantitative fashion based on the percentage of positive tumor cells: <10%, focal; 10% to 25%, 1+; 26% to 75%, 2+; > or =76%, 3+. All 113 PPAs exhibited strong, diffuse CK7 expression. With respect to CK20 expression, 17 of the 19 cases (89.4%) of mucinous BAC showed moderate to strong expression of this protein, whereas only 10 cases of conventional adenocarcinomas and 4 cases of nonmucinous BAC exhibited expression. All 6 examples of metastatic colonic adenocarcinomas were negative for CK7 and strongly positive for CK20. In summary, mucinous BAC is distinct from other PPAs by virtue of its CK20 expression. Although the CK7/CK20 immunoprofile is a valuable diagnostic marker for differentiating primary lung adenocarcinoma from metastatic colonic adenocarcinoma, caution should be exercised when dealing with mucinous BAC.
黏液性细支气管肺泡癌（BAC）在临床和形态学上都可能与肺转移性腺癌极为相似。多项研究表明，细胞角蛋白7（CK7）和细胞角蛋白20（CK20）的差异表达是区分原发性肺腺癌（PPA）（通常CK7阳性/CK20阴性）与转移性结肠腺癌（通常CK7阴性/CK20阳性）的一种有价值的诊断工具。本研究旨在将PPA的组织学亚型与CK7和CK20的表达相关联。总共选取了113例确诊的PPA，并根据1999年世界卫生组织标准分为腺癌，未特指型（n = 80）、非黏液性BAC（n = 14）和黏液性BAC（n = 19）。对所有肿瘤的代表性切片进行CK7和CK20表达的免疫组织化学分析。为评估CK7和CK20表达的诊断效用，用相同抗体检测了6例肺转移性结肠腺癌，并与黏液性BAC进行比较。结果以半定量方式基于阳性肿瘤细胞百分比表示：<10%，局灶性；10%至25%，1+；26%至75%，2+；≥76%，3+。所有113例PPA均表现出强的、弥漫性CK7表达。关于CK20表达，19例黏液性BAC中有17例（89.4%）显示该蛋白中度至强表达，而只有10例传统腺癌和4例非黏液性BAC表现出表达。所有6例转移性结肠腺癌CK7均为阴性，CK20强阳性。总之，黏液性BAC因其CK20表达而与其他PPA不同。虽然CK7/CK20免疫表型是区分原发性肺腺癌与转移性结肠腺癌的一种有价值的诊断标志物，但在处理黏液性BAC时应谨慎。
