Smooth muscle myosin heavy chain 1 by IHC

Alphabetical Test listing

Smooth muscle myosin heavy chain 1 by IHC-12376 - Technical only, 12379 - Technical & interpretation

Smooth muscle myosin heavy chain 1 by IHC
12376 - Technical only, 12379 - Technical & interpretation
  • All IHC stains will include a positive control tissue
  • SMMSHC-1 will stain myoepithelial cells of ducts and acini in normal breast lobules. It will also react with vascular smooth muscle
  • SMMSHC-1 reacts with the intact myoepithelial cell layer present in benign and in situ breast lesions. It is useful in distinguishing benign breast and DCIS from invasive tumors of the breast
  • Rarely, reactivity is seen with myofibroblasts in desmoplastic stroma of invasive carcinoma (5 of 70 cases). When positive, only rare stromal cells were immunostained. 1
  • Myoepithelial layers in complex sclerosing lesions and papillomas stain positively along papillary fronds with SMMSHC-1 but no myoepithelial immunostaining along the papillary fronds has been observed in intracystic papillary carcinoma
  • SMMSHC-1 has been reported to label neoplastic myoepithelium of pleomorphic adenomas of the salivary gland 2
  • It is not yet known how SMMSHC-1 reacts in micro-glandular adenosis. Micro-glandular adenosis is a benign lesion of the breast composed of a single layer of epithelial cells, which has been reported to be devoid of a surrounding myoepithelial layer (i.e. MSA negative).

Submit a formalin-fixed, paraffin embedded tissue block


Formalin-fixed, paraffin embedded (FFPE) tissue block


FFPE tissue section mounted on a charged, unstained slide


Ambient (preferred)

  • Unlabeled/mislabeled block
  • Insufficient tissue
  • Slides broken beyond repair
AHL - Immunohistochemistry
Mo - Fr
1 - 2 days

Immunohistochemical staining and microscopic examination


If requested, an interpretive report will be provided



  • Antibody recognizes a cytoplasmic protein (SM-MHC, smooth muscle myosin heavy chain) which is a major component of the contractile apparatus in smooth muscle cells
  • 2 isoforms of SM-MHC exist: SM1 (204 kd) and SM2 (200 kd). Both isoforms are expressed in smooth muscle cells (markers of terminal smooth muscle differentiation)

Staining pattern

  • Cytoplasmic based


  1. Wang et al: Antibodies to Novel Myoepithelium - Associated Proteins Distinguish Benign Lesions and Carcinoma in Situ From Invasive Carcinoma of the Breast; Applied Immunohistochemistry; 5(3):141-151, 1997.
  2. Data Sheet, DAKO.
88342 - 1st stain
88341 - each additional stain