HER2-low unresectable and/or metastatic breast cancer in Russia

Inclusion Criteria

• - Patients with confirmed diagnosis of unresectable and/or metastatic BC established between the 1st July 2021 and the 1st July 2022.
• - Patients have HER2-negative status (IHC0, IHC1+, IHC2+/ISH-) obtained in the local laboratory.
• -. Patients have an adequate archival tumor sample and slides suitable for reassessment HER2 status* by the reference laboratory.
• - Patients have documented hormonal status (ER, PR) IHC score.
• - Age ≥ 18 years at the time of inclusion.
• - Patients provided written consent allowing for data and samples to be used in the future and this study would be covered by the consent for future use in accordance with ICH GCP, GPP (Good Pharmacoepidemiology Practices) and local law prior to inclusion in the study. If the patient is deceased, a waiver may be accepted