Compared with their luminal B counterparts, luminal A tumors generally are lower grade, have higher expression of estrogen-related genes, have a better prognosis, and are more sensitive to endocrine therapy.
Luminal B tumors are ER positive, HER2 positive or negative and at least one of the following: KI-67 20% or greater, PR negative or less than 20% and high recurrence rate based on multiple gene expression assay.
Luminal B high risk signatures correlate with lower expression of ER, PR, or both, a higher grade, and greater proliferation with a higher risk of recurrence.