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

Test name:

Test number:

12376 - Technical only, 12379 - Technical & interpretation

Excellian order number:

LAB12376
LAB12379

Alternate names:

SMMS

Tests included:

All IHC stains will include a positive control tissue

Useful for:

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).

Specimen type:

Tissue

Processing instructions:

Submit a formalin-fixed, paraffin embedded tissue block

Transport container:

Formalin-fixed, paraffin embedded (FFPE) tissue block

Alternate transport container:

FFPE tissue section mounted on a charged, unstained slide

Transport and stability:

Ambient (preferred)

Reason for rejection:

Unlabeled/mislabeled block
Insufficient tissue
Slides broken beyond repair

Performing lab:

AHL - Immunohistochemistry

Days set up:

Mo - Fr

TAT:

1 - 2 days

Method:

Immunohistochemical staining and microscopic examination

Reference ranges:

If requested, an interpretive report will be provided

Clinical information:

Specifications

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

References

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.
Data Sheet, DAKO.

CPT codes:

88342 - 1st stain
88341 - each additional stain

Date created:

09/06/2017

Revised date:

10/17/2018

Review date:

01/12/2024