Stains & CD markers

Topic Completed: 1 May 2013

Minor changes: 10 September 2021

Copyright: 2002-2021,, Inc.

PubMed Search: INI1[TI]

Lauren N. Stuart, M.D., M.B.A.
Page views in 2020: 13,237
Page views in 2021 to date: 13,515
Cite this page: Stuart L. INI1 / SMARCB1. website. Accessed October 21st, 2021.
Definition / general
  • Expressed in all cell types; involved in chromatin remodeling and transcriptional regulation (Histopathology 2012;61:1245)
  • Also called hSNF5, SMARCB1 and BAF47
Clinical features
Uses by pathologists
  • Diagnosis of CNS atypical teratoid / rhabdoid tumors, renal medullary carcinoma and rhabdoid tumors (loss of expression)
  • Distinguish atypical teratoid / rhabdoid tumor (loss of INI1) from choroid plexus carcinoma (INI1+, J Neuropathol Exp Neurol 2005;64:391)
  • Differentiate epithelioid sarcoma (loss of INI1) from epithelioid hemangioendothelioma (INI1+, Am J Surg Pathol 2009;33:542)
Microscopic (histologic) images

Images hosted on other servers:

Composite rhabdoid tumors

Epithelioid sarcoma (INI1-)

Synovial sarcoma

With rhabdoid features

Positive staining - normal
  • Most normal cells
Positive staining - disease
  • Composite rhabdoid tumors, including rhabdoid meningioma (Mod Pathol 2005;18:951), synovial sarcoma (but reduced levels in 65%, Mod Pathol 2010;23:981)
  • Renal cell carcinoma or urothelial carcinoma, including those with histological rhabdoid features
  • Retained expression in epithelioid sarcoma-like hemangioendothelioma
Negative staining
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