Practical application of lineage-specific immunohistochemistry markers: Transcription factors (Sometimes) behaving badly

Si Kei Lou, Oyedele A. Adeyi

Research output: Contribution to journalReview articlepeer-review

4 Scopus citations


Context. - Transcription factors (TFs) are proteins that regulate gene expression and control RNA transcription from DNA. Lineage-specific TFs have increasingly been used by pathologists to determine tumor lineage, especially in the setting of metastatic tumors of unknown primary, among other uses. With experience gathered from its daily application and increasing pitfalls reported from immunohistochemical studies, these often-touted highly specific TFs are not as reliable as once thought. Objectives. - To summarize the established roles of many of the commonly used TFs in clinical practice and to discuss known and potential sources for error (eg, false-positivity from cross-reactivity, aberrant, and overlap "lineage-specific" expression) in their application and interpretation. Data Sources. - Literature review and the authors' personal practice experience were used. Several examples selected from the University Health Network (Toronto, Ontario, Canada) are illustrated. Conclusions. - The application of TF diagnostic immunohistochemistry has enabled pathologists to better assess the lineage/origin of primary and metastatic tumors. However, the awareness of potential pitfalls is essential to avoid misdiagnosis.

Original languageEnglish (US)
Pages (from-to)626-643
Number of pages18
JournalArchives of Pathology and Laboratory Medicine
Issue number5
StatePublished - May 2020

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