Penman D, Downie I, Roberts F
Department of Pathology, University of Glasgow, Western Infirmary, Glasgow, UK.
J Clin Pathol. 2006 Jun;59(6):663-4. doi: 10.1136/jcp.2005.030064.
Immunohistochemistry for thyroid transcription factor-1 (TTF-1) is considered an important ancillary technique for distinguishing primary pulmonary adenocarcinomas from metastases. A case of metastatic colonic adenocarcinoma in a bronchial biopsy specimen that showed focal positive nuclear staining for TTF-1 is reported here. The primary colonic adenocarcinoma was retrieved from the file and immunostaining also showed focal nuclear positivity for TTF-1. This confirmed the morphological and clinical impression of colonic metastases in the bronchial biopsy specimen. To investigate this apparent aberrant TTF-1 expression, further sections from primary colonic adenocarcinoma were immunostained for TTF-1 using the SPT24 antibody clone. Three of the six cases studied showed focal nuclear positivity with the SPT24 clone. All six cases were subsequently shown to be negative with the 8G7G1 clone. It is concluded that the SPT24 antibody to TTF-1 may show focal nuclear positivity in adenocarcinomas of colorectal origin such that focal staining in small biopsy specimens should be interpreted with caution.
甲状腺转录因子-1（TTF-1）免疫组化被认为是鉴别原发性肺腺癌与转移癌的一项重要辅助技术。本文报告了1例支气管活检标本中转移性结肠腺癌显示TTF-1局灶性核阳性染色的病例。从存档中找回原发性结肠腺癌，免疫染色也显示TTF-1局灶性核阳性。这证实了支气管活检标本中结肠转移瘤的形态学和临床印象。为研究这种明显异常的TTF-1表达，使用SPT24抗体克隆对原发性结肠腺癌的更多切片进行TTF-1免疫染色。所研究的6例病例中有3例显示SPT24克隆局灶性核阳性。随后所有6例病例用8G7G1克隆检测均为阴性。结论是，TTF-1的SPT24抗体在结直肠来源的腺癌中可能显示局灶性核阳性，因此对小活检标本中的局灶性染色应谨慎解读。
