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Table of Contents
Definition / general | Terminology | Pathophysiology | Clinical features | Interpretation | Uses by pathologists | Microscopic (histologic) images | Positive staining - normal | Positive staining - disease | Negative stainingCite this page: Stuart L. Microphthalmia transcription factor (MITF). PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/stainsmitf.html. Accessed May 26th, 2019.
Definition / general
- Encodes a transcription factor on chromosome 3p14.1 essential for development and survival of melanocytes (Am J Surg Pathol 2001;25:51)
Terminology
- Also known as MI, WS2, CMM8, WS2A, bHLHe32 (Entrez Gene: MITF microphthalmia-associated transcription factor)
Pathophysiology
- Plays key role in transcription regulation of pigmentation enzyme genes tyrosinase and tyrosinase-related proteins 1 and 2
- Acts with Ets family factor PU.1 to activate TRAP gene
- Regulates expression of cathepsin K in osteoclasts (Mod Pathol 2012;25:100)
- Regulates function of pancreatic beta cells and may play a role in glucose homeostasis (Diabetes 2013;62:2834)
Clinical features
- Heterozygous mutations cause Waardenburg syndrome IIA (autosomal dominant, white forelock and hearing loss)
Interpretation
- Nuclear immunostain
Uses by pathologists
- Diagnosis of perivascular epithelioid cell tumors including angiomyolipoma (Am J Surg Pathol 2001;25:65)
- Diagnosis of melanoma and other melanogenic tumors
Microscopic (histologic) images
Images hosted on other servers:
Giant cell tumor of bone, 1C
Positive staining - normal
- Macrophages / histiocytes (Am J Surg Pathol 2001;25:197), mast cells, melanocytes, osteoclasts, perivascular epithelioid cells (Mod Pathol 2012;25:100)
Positive staining - disease
- Melanoma (usually negative in desmoplastic melanomas, J Cutan Pathol 2010;37:944, Am J Surg Pathol 2001;25:205) and nevi
- Perivascular epithelioid tumors including angiomyolipoma, clear cell myomelanocytic tumors of falciform ligament / ligamentum teres
- Clear cell sarcoma (2/3), giant cell tumor (Arch Pathol Lab Med 2005;129:360)
- Variable results for neurothekeoma (Mod Pathol 2004;17:230, J Cutan Pathol 2014;41:640)
Negative staining
- Basal cells, epithelium, peripheral nerve sheath, smooth muscle
- Atypical fibroxanthomas, carcinoma, fibrohistiocytic lesions (Am J Surg Pathol 2001;25:51), germ cell tumors, malignant peripheral nerve sheath tumor, melanocytic schwannoma, neurofibromas, palisaded and encapsulated neuroma
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