ESR1 and neoplasm: As expected, tumours that shifted from LumB to LumA demonstrated higher expression of LumB correlation coefficients, differentiation scores, ESR1, genomic risk, and interferon-gamma signatures, and lower expression of LumA score, PGR, claudin-low, mast cells, stroma, and mammary stemness compared to tumours that remained LumA throughout treatment (Supplementary Figure S4).