[Histonet] Myofbroblast markers

peptolab peptolab <@t> hamptons.com
Tue Apr 6 16:43:53 CDT 2004

I like alpha smooth muscle actin- no antigen retrieval necessary in FFPE
tissues. Cross reactivity with smooth muscle should not be a problem in most
systems or tissues other than gut.
Some use desmin but I think actin stains more varieties/functional states of
myofibroblasts than desmin. I think there is tremendous heterogeneity among
myofibroblasts in different tissue- I concentrate on those in connective
 Additionally I believe that the ubiquitous interstitial CD34+
fibroblast-like cell found in most collagenous connective tissue and fat are
myofibroblast precursers- acting as reserve cells for tissue repair and
remodelling. In my surgical pathology work- some (mesenchymal)
myofibroblastic tumors of skin, breast and soft tissue have maintained CD34
expression as well as actin, a neoplastic myofibroblast phenotype,  though
in healing wounds and other reactive lesions or even in malignant epithelial
tumor stroma - indigenous fibroblasts almost always lose CD34 expression
when they transform (if you believe they do)  to actin+ myofibroblasts. Just
some food for thought

Jeff Silverman HT HTL QIHC (ASCP)
Pathologists' Assistant
Southside Hospital
Bay Shore New York

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