the world with regard to race and ethnicity[2,4,5]. Despite the rapid
expansion of novel diagnostics designed to personalize breast cancer
care[6], there remain several significant unmet needs for improving
the accuracy and reproducibility of tests that are already in common
daily clinical practice[7].
Over the past decades, breast tumor markers such as estrogen
receptor (ER), progesterone receptor (PR), human epidermal growth
factor receptor 2 (HER2) have become very useful in predicting
prognosis and determining therapy options for patients with breast
cancer. This has been particularly helpful in identifying those patients
who would benefit from antiestrogen therapy and also those who
would likely respond to HER2-based therapy. The effective use of