TFF3 was undetectable in healthy donor blood samples and more frequently detected in the CTC fraction of breast cancer patients with advanced compared to early-stage disease, similarly to other reports demonstrating an association with breast cancers progressed to bone metastases [38] and leptomeninges [39], and listing TFF3 among those genes belonging to a specific genomic region that frequently undergoes copy number gain at CTC level in the metastatic setting [40]. The gene discussed is TFF3; the disease is breast cancer.