Stains
Smooth muscle myosin heavy chain / SMMHC


Topic Completed: 1 January 2017

Revised: 20 September 2019

Copyright: 2017-2019, PathologyOutlines.com, Inc.

PubMed search: SMMHC

Rebecca Obeng, M.D.
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Cite this page: Obeng R. Smooth muscle myosin heavy chain / SMMHC. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/stainssmmhc.html. Accessed November 19th, 2019.
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
Terminology
  • Myosin heavy chain 11, myosin 11, myosin heavy chain, smooth muscle isoform, MYH11, SMHC, SMMHC
Sites
  • Expressed in cytoplasm and cell membrane of myoepithelial and smooth muscle cells
Pathophysiology
Diagnosis
Laboratory
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
(cytoplasmic staining) in breast tissue



Images hosted on other servers:

Positive stains:

Colon

Endometrium

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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