Stains & CD markers
Smooth muscle myosin heavy chain / SMMHC

Last author update: 1 January 2017
Last staff update: 5 September 2023

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PubMed search: SMMHC

Rebecca Obeng, M.D.
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Cite this page: Obeng R. Smooth muscle myosin heavy chain / SMMHC. website. Accessed October 2nd, 2023.
Definition / general
  • The MYH11 gene (Chromosome 16) encodes a smooth muscle myosin protein (SMMHC) that is a subunit of a hexameric protein involved in contraction, the conversion of chemical energy into mechanical energy via ATP hydrolysis, and G protein coupled receptors / GPCR signaling
  • Fusion between core binding factor beta (CBF-beta) with SMMHC (CBFbeta-SMMHC; Inv(16)(p13q22)) is present in nearly all acute myeloid leukemia M4 eosinophilia subtype (AML M4Eo)
  • Useful for differentiating between benign and malignant lesions (e.g. breast and lung lesions)
Essential features
  • Myosin heavy chain 11, myosin 11, myosin heavy chain, smooth muscle isoform, MYH11, SMHC, SMMHC
  • Expressed in cytoplasm and cell membrane of myoepithelial and smooth muscle cells
Microscopic (histologic) description
  • Cytoplasmic and membranous staining in normal myoepithelial and smooth muscle cells
  • Nuclear staining in acute myeloid leukemic cells with Inv(16)
Microscopic (histologic) images

Contributed by Rebecca Obeng, M.D.

SMMHC staining myoepithelial cells

Images hosted on other servers:

Positive stains:



Various images

Cytology description
  • Positive immunohistochemical staining in spindle cells between epithelial cells or along the edges of epithelial cells in benign breast lesions; negative staining in invasive breast carcinomas except for vascular smooth muscle cells (Diagn Cytopathol 1999;20:203)
Positive stains
Flow cytometry description
  • Intracellular staining for CBFbeta-SMMHC can be used for the identification of AML M4Eo leukemic cells (Blood 1998;91:1882)
Molecular / cytogenetics description
  • Inv(16)(p13q22) or t(16:16)(p13q22) leads to fusion of CBFbeta and SMMHC that can be detected by fluorescent in situ hybridization
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