Stains
Smooth muscle myosin heavy chain / SMMHC

Author: Rebecca Obeng, M.D. (see Authors page)

Revised: 14 February 2017, last major update January 2017

Copyright: (c) 2017, PathologyOutlines.com, Inc.

PubMed search: SMMHC

Cite this page: Smooth muscle myosin heavy chain / SMMHC. PathologyOutlines.com website. http://pathologyoutlines.com/topic/stainssmmhc.html. Accessed August 21st, 2017.
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

Images hosted on PathOut server:

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



Negative stains:

Liver

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