XBP1 and breast cancer: Among the top-100 most significantly repressed genes in our RNA-Seq data (|log FC| ≥ 1.5 and adjusted P-value < 1e-10) we found at least 8 BC luminal markers (including ESR1, GATA3, TFF1, TFF3, MYB, XBP1, MUC1, CRABP2) [43].