ESR1 and triple-negative breast carcinoma: Data from three independent studies, including ours, demonstrated that 10 of 14 triple-negative breast cancer (TNBC) cell lines were sensitive to TRAIL-induced apoptosis, whereas only two of eight HER2-amplified cell lines, and none of seven estrogen receptor (ER)-positive lines were sensitive to TRAIL-induced apoptosis [5,15,19,20].