In addition, C1orf64 closely correlated with AR expression in primary and metastatic breast tumors and C1orf64 expression was relatively higher in breast tumors with a lower grade and lobular histology.
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.
Here we have developed and validated a real-time RT-PCR assay to quantify AR gene expression at the mRNA level in a series of 131 patients with unilateral invasive primary breast tumors.
Characterization of androgen receptor and nuclear receptor co-regulator expression in human breast cancer cell lines exhibiting differential regulation of kallikreins 2 and 3.
Re-evaluation of the breast tumor immunohistochemistry has shown positive androgen receptor expression and negative expression for estrogen, progesterone and HER-2 receptors.
A majority (~70%) of breast tumors are found to express estrogen receptor, and a significant portion (~90%) of ER-positive (ER<sup>+</sup>) breast tumors are also androgen receptor-positive (AR<sup>+</sup>).
Lack of expression of androgen receptor may play a critical role in transformation from in situ to invasive basal subtype of high-grade ductal carcinoma of the breast.
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).
Eligible studies were identified by systematic review of electronic databases using the MeSH-terms "breast neoplasm" and "androgen receptor" and were selected after a qualitative assessment based on the REMARK criteria.
Transgenic introduction of androgen receptor into estrogen-receptor-, progesterone-receptor-, and androgen-receptor-negative breast cancer cells renders them responsive to hormonal manipulation.
Furthermore, gene encoding coagulation factor VII (F7) demonstrated the closest expression pattern with AR (CC=0.716) in the dataset and factor VII protein expression was significantly associated to that of AR in a cohort of 209 breast tumors.