Recent advances in the molecular classification of breast tumours have uncovered a subset of breast tumours associated with high expression of androgen receptor mRNA including the so-called 'luminal androgen receptor (LAR) tumours' and 'molecular apocrine tumours' (MATs).
Significant differences in AR levels existed among different breast tumor subtypes (highest in estrogen receptor-positive and/or progesterone receptor-positive tumors) as well as by PIK3CA mutation status (P < 0.0001 for both).
These findings are in agreement with the hypothesis that AR may stimulate or inhibit breast cancer growth depending on ER status, AR transactivation, and the endocrine-metabolic environment of breast tumors.
To get more insight into the role of AR in breast cancer, we additionally performed a retrospective pooled analysis to determine the prognostic value of the AR using mRNA profiles of 7270 primary breast tumors.
Transgenic introduction of androgen receptor into estrogen-receptor-, progesterone-receptor-, and androgen-receptor-negative breast cancer cells renders them responsive to hormonal manipulation.