Submit a formalin-fixed, paraffin embedded tissue block

FFPE tissue block

Tissue section mounted on a charged, unstained slide

Ambient (preferred)

• Unlabeled/mislabeled block
• Insufficient tissue
• Slides broken beyond repair

Immunohistochemical staining and microscopic examination

If requested, an interpretive report will be provided

Specifications

SMARCA4 (SWI/SNF related, matrix associated, actin dependent regulator of chromatin, subfamily A, member 4) encodes BRG1, a protein of the WSI/SNF complex involved in chromatic remodeling. SMARCA4-deficient neoplasms have undifferentiated, often rhabdoid morphology and demonstrate loss of BRG1 immunohistochemical nuclear expression.

Staining pattern

Nuclear staining in normal tissues. Loss of nuclear staining is present in SMARCA4/BRG1 deficient tumors.

Small cell carcinoma of the ovary hypercalcemic type with loss of nuclear staining; lymphocytes and endothelial cells serve as positive internal controls

Applications

• Loss of SMARCA4/BRG1 characterizes small cell carcinoma of the ovary hypercalcemic type, SMARCA4 deficient undifferentiated uterine sarcoma, and SMARCA4 deficient thoracic carcinomas/sarcomas and demonstrate rhabdoid or poorly differentiated morphology.
• BRG1 loss has been described in a subset of melanomas, epithelioid mesotheliomas, lung adenocarcinomas, and lung squamous cell carcinomas.

References

1. Conlon N, Silva A, Guerra E eta l. Loss of SMARCA4 expression is both sensitive and specific for the diagnosis of small cell carcinoma of ovary, hypercalcemic type. Am J Surg Pathol 2016;40(3):395-403.
2. Nambirajan A, Singh V, Bhardway N et al. SMARCA4/BRG1-Deficient non-small cell lung carcinomas- A case series and review of the literature. Arch Pathol Lab Med. 2020 doi: 10.5858/arpa.2019-0633-OA