Breast Cancer tumour subtypes
Luminal A: ER+* and/or PR+ and HER2- (42-59% prevalence)
Luminal B: ER+ and/or PR+ and HER2+ (6-19%)
HER2 overexpressing: ER- and/or PR- but HER2+ (7-12%)
Triple negative/basal-like: negative for all three (above), cytokeratin 5/6 + and/or HER1+ (15-20%)

*Key
ER: (o)estrogen receptor
PR: progesterone receptor
HER: Human epidermal growth factor receptor

Oncotype DX assay (USA): first breast cancer test that provides individual, quantitative assessment of the likelihood of disease reoccurrence. This test would be useful for women who are node negative and making a decision around undergoing chemotherapy or not.