Desmin is a protein exrpessed in cells in normal smoth, skeletal and cariac muscle. This is useful in immunohistochemistry as a positive result can help determine if the tumour has a myogenic origin and components.

Identification of smooth muscle and skeletal muscle tumours. The staining pattern of Desmin is cytoplasmic as shown below.

Picture 1 – Desmin positivity in Heart

 

Desmin has several different applications. Below are a few examples.

Tumour or cell type	Desmin + or -
Leiomyosarcoma	Positive
Rhabdomyosarcoma	Positive
Spindle cell carcinoma	Negative
Adenocarcinoma	Negative