Analysis of Circulating Tumor DNA (ctDNA) in HER2-low Advanced/Metastatic Breast Cancer

Prospective single-center feasibility study of 30 patients with carcinoma breast with low levels of HER2 expression, defined as 1+ or 2+ expression levels by the IHC technique (immunohistochemistry) and the gene not amplified by the ISH test (in situ hybridization)

Inclusion criteria

• Participants diagnosed with HER2-low breast cancer, defined as IHC score 1+ or 2+ and not amplified at in situ hybridization (ISH) test as confirmed by local laboratory testing.
• Participants should be at advanced or metastatic setting prior to treatment.
• Written informed consent (Accordo di Partecipazione alla Ricerca Scientifica) and specific informed consent to the study must be signed and dated by the patient and the doctor prior to inclusion.
• Patients must be accessible for follow-up.