ESR1 and breast carcinoma: Using the same combined datasets, following adjustment to these well-established concepts, we stringently determined in multivariate analyses that EEF1A1 mRNA underexpression is an independent prognostic biomarker for ER+ (p = 9.0 × 10−9 and p = 0.0329) but not ER- breast cancers (p = 0.8796, p = 0.6672; Table 1).