Demonstration of myoepithelial cells can confirm the in situ or benign nature of a process while their absence supports invasion
We prefer to use both p63 and calponin on problematic cases
A variety of markers have been used for myoepithelial cells:
Marker
Sensitivity
Specificity
Calponin
Excellent
Very good
p63
Excellent
Excellent
Smooth muscle myosin heavy chain
Good
Excellent
CD10 (CALLA)
Good
Good
High molecular weight cytokeratin
Very good
Poor
Maspin
Good
Poor
S100
Good
Very poor
Actin
Good
Very poor
Estrogen receptor (ER) and progesterone receptor (PR) are important markers for directing therapy and determining prognosis
Current consensus is that any level of positivity should be reported as positive
Medullary carcinomas are reported to be negative in 90% of cases
Her2neu status can be determined by either immunohistology or by FISH
The other technique can be used for borderline cases
Medullary carcinomas are reported to be negative in 94% of cases
Genetics
Medullary carcinoma is associated with BRCA1 germ line mutations in a minority of cases, but increased compared to the general population (2 of 18 cases tested)
