[Transcription factors in tumor diagnosis]

Transcription factors are a heterogeneous group of DNA-binding proteins that regulate the transcription of distinct genes. Due to their cell-type specificity and cell lineage restriction, numerous transcription factors have been established in recent years as excellent, sensitive, and specific immunohistochemical tumor markers. As compared to other cytoplasmic and membranous differentiation markers, the nuclear immunolocalization of transcription factors is often more stably preserved. Therefore, cell lineage-specific transcription factors can be detected even in poorly differentiated metastatic tumors. However, for their reliable diagnostic use, detailed knowledge is required on their expression profiles, which are often more complex than initially assumed.CDX2 is a sensitive marker for colorectal adenocarcinomas but is also expressed in upper abdominal adenocarcinomas, mucinous carcinomas of lung and ovary, and midgut neuroendocrine tumors. A higher degree of specificity for colorectal origin is provided by SATB2. TTF-1 is a valuable marker particularly for pulmonary adenocarcinomas, but may also be focally expressed "aberrantly" in abdominal and gynecological adenocarcinomas. GATA3 is found in breast and urothelial carcinomas but also in squamous cell carcinomas. PAX8 is a highly sensitive marker of all subtypes of gynecological adenocarcinomas, renal cell carcinomas, and thyroid carcinomas. Further transcription factors characterized by molecular biology have meanwhile become diagnostically relevant, the number of which is increasing.Principally, for the diagnostic use of transcription factors as immunohistochemical tumor markers, clinical and radiological data as well as conventional histopathology should always be carefully considered and if necessary they should be applied in the context of a marker panel.