ESR1 and neoplasm: We performed global gene expression profiling from the isolated iCTCs and found upregulation of multiple cell lineage–progenitor potency (DTR, SOX1, FGFR2, NOTCH1, FOLH1, NEUROG2, FLT3LG, TEKT3, CDH5, FLT4, TEK), tumor immune response (DPP4/CD26), cytokeratin genes (KRT8, KRT16, KRT17, and KRT19), and tumor-associated genes (TERT, MUC16/M17S2/CA125, CD44, TWIST1, TACSTD1/EpCAM/CD326/ESA/HEA125/GA733, DPP4/CD26, ESR1, and PGR).