Differently from published data, our research demonstrates that TFF3 is detectable at mRNA level and as a secreted peptide in MDA-MB-231 cells in vitro, although higher expression was observed when comparing EpCAM-enriched to HER2/EGFR-enriched CTCs, consistently with its frequent detection in the luminal and more epithelial-like breast cancers. Here, ERBB2 is linked to breast cancer.