PGR and breast cancer: Many researchers evaluated the quantitative capability of RPPA using several pathological markers and found that human epidermal growth factor receptor 2 (HER2) exhibited nearly 100% concordance rate based on a SuperCurve signal intensity cutoff of 1600 in a cohort of 35 breast cancer samples but not for estrogen receptor (ERα) and progesterone receptor (PR) assayed simultaneously19.