Clinical Study on the Application of 18F-HER2 Affibody PET Imaging in HER2-Expressing Breast Cancer

Human epidermal growth factor receptor 2 (HER2) is a transmembrane receptor protein with tyrosine kinase activity that plays a crucial role in cell growth, activation, and proliferation. While minimally expressed in normal tissues, HER2 is highly expressed in various malignant tumors, especially breast cancer, making it a key target for breast cancer diagnosis and treatment.HER2-positivity was defined with Immunohistochemistry (IHC) 3+ or IHC 2+ followed by Fluorescence In Situ Hybridization（FISH） showing HER2 amplification.HER2-low was defined IHC 1+ or IHC 2+ with negative FISH . Conventional diagnostic approaches like biopsy are inherently invasive and lack the capability for longitudinal evaluation of HER2 expression dynamics.The HER2-targeted Affibody molecule demonstrates superior diagnostic potential compared to traditional antibodies, attributed to its enhanced specificity, compact molecular structure enabling rapid biodistribution (achieving optimal blood clearance within 1-4 hours post-injection), and consequent high-contrast imaging capabilities. As a novel positron emission tomography (PET) tracer, 18F-HER2 Affibody holds promise for delivering precise, non-invasive quantification of HER2 status. This study seeks to systematically assess the diagnostic accuracy of 18F-HER2 Affibody PET in tumor staging and treatment stratification, while concurrently investigating its prognostic value through longitudinal treatment response monitoring in breast cancer patients with HER2-overexpressing tumors.

Inclusion criteria

• Age 18-75 years, ECOG score 0 or 1.
• Clinically or pathologically confirmed diagnosis of patients with HER2 expression breast cancer or suspected expression breast cancer.
• Life expectancy ≥ 12 weeks.
• At least one measurable target lesion according to RECIST 1.1 criteria.
• All participants of reproductive potential (regardless of gender) must commit to using effective contraceptive methods throughout the trial participation and for 6 months after the last PET scan.
• Ability to understand and voluntarily sign the informed consent form, with good compliance.

Exclusion criteria

• Severe hepatic or renal dysfunction.
• Pregnant or lactating women, or women planning to become pregnant.
• Inability to lie supine for half an hour.
• Refusal to participate in this clinical study.
• Suffering from claustrophobia or other mental illnesses.
• Other conditions that the investigator deems unsuitable for participation in the trial.