Assessment of HER2 status in breast cancer: why, when and how?
Human epidermal growth factor receptor 2 (HER2) is overexpressed, usually as a result of HER2 proto-oncogene amplification, in 20-30% of breast cancers. A HER2-positive status is generally associated with more aggressive disease and a worse prognosis. Furthermore, a positive HER2 status may predict the likelihood of resistance to some conventional therapies, as well as probably being predictive of sensitivity to anthracycline dose intensification. In addition to this prognostic/predictive value, HER2 is a target for specific therapy, with anti-HER2 monoclonal antibody therapy available in the USA. This article reviews the different assays used to determine HER2 status, discussing their relative advantages/disadvantages and the need for their standardisation before integration alongside other pathological indices into the clinical management of breast cancer.
Dowsett
M
M
Academic Department of Biochemistry, Royal Marsden Hospital, London, UK. mitch@icr.ac.uk
Cooke
T
T
Ellis
I
I
Gullick
W J
WJ
Gusterson
B
B
Mallon
E
E
Walker
R
R
D014408:Biomarkers, Tumor / Q000032:analysis; D001943:Breast Neoplasms / Q000188:drug therapy / Q000473:pathology*; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D009363:Neoplasm Proteins / Q000032:analysis*; D000090063:Proto-Oncogene Mas; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000032:analysis*
D014408:Biomarkers, Tumor; D009363:Neoplasm Proteins; D000090063:Proto-Oncogene Mas; D018719:Erb-b2 Receptor Tyrosine Kinases; C000715470:MAS1 protein, human