Stains & CD markers
SMARCA4 / BRG1

Editor-in-Chief: Debra L. Zynger, M.D.
Susan M. Armstrong, M.D., Ph.D.
Brendan C. Dickson, M.D., M.Sc.

Last author update: 21 March 2023
Last staff update: 21 March 2023

Copyright: 2002-2023, PathologyOutlines.com, Inc.

PubMed Search: SMARCA4 / BRG1

Susan M. Armstrong, M.D., Ph.D.
Brendan C. Dickson, M.D., M.Sc.
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Page views in 2023 to date: 9,450
Cite this page: Armstrong SM, Dickson BC. SMARCA4 / BRG1 . PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/stainsSMARCA4BRG1.html. Accessed September 25th, 2023.
Definition / general
Essential features
Pathophysiology
Clinical features
Interpretation
  • SMARCA4 has a nuclear pattern of immunohistochemical expression; SMARCA4 deficient neoplasms have complete loss of staining among tumor cells with retained expression by nonneoplastic tissues (e.g., blood vessels, lymphocytes) (Nature 1993;366:170)
  • There is no established cutoff for determining high versus low expression; staining of the surrounding normal tissue has been used as a median value relative to which SMARCA4 expression may be considered increased or decreased (Int J Oncol 2013;42:403)
Uses by pathologists
Prognostic factors
  • Concomitant loss of SMARCA4 and BRM in non-small cell lung cancer is associated with worse prognosis (Cancer Res 2003;63:560)
  • Loss of expression of SMARCA4 is associated with improved prognosis in clear cell renal cell carcinoma (Oncotarget 2017;8:37423)
  • Increased SMARCA4 expression is associated with worse prognosis in patients with breast invasive ductal carcinoma, hepatocellular carcinoma and clear cell renal cell carcinoma (Anticancer Res 2016;36:4873, Sci Rep 2018;8:2043)
Microscopic (histologic) images

Contributed by Rose Chami, M.D. and Catherine Chung, M.D.
Ovarian small cell carcinoma, hypercalcemic type Ovarian small cell carcinoma, hypercalcemic type

Ovarian small cell carcinoma, hypercalcemic type

Positive staining - normal
  • Most normal tissues contain intact nuclear SMARCA4 expression
Positive staining - disease
Negative staining
Molecular / cytogenetics description
  • In small cell carcinoma of the ovary, whole exome sequencing demonstrated:
  • In SMARCA4 deficient thoracic tumors, mRNA sequencing showed the presence of SMARCA4 gene mutations (nonsense, frameshift, missense and splice site) (Nat Genet 2015;47:1200)
Sample pathology report
  • Immunohistochemical analysis of SMARCA4 / BRG1 expression (clone, dilution, automated staining platform*):
    • The tissue staining pattern is intact / lost.*
    • External (positive and negative) and internal (e.g., endothelial cells and lymphocytes) controls have intact staining pattern.*
  • *Details to be specified / confirmed upon reporting stain.
Board review style question #1

Which of the following is associated with loss of SMARCA4 expression?

  1. Colorectal adenocarcinoma
  2. Melanoma
  3. Small cell carcinoma of the lung
  4. Small cell carcinoma of the ovary, hypercalcemic type
Board review style answer #1
D. Small cell carcinoma of the ovary, hypercalcemic type

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Reference: SMARCA4 / BRG1
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