A novel radiotracer 99mTc-RWY targeting Integrin α6 was developed, and the pilot first-in-human study for SPECT imaging of breast cancer was performed in seven healthy volunteers and two breast cancer patients to assess the safety and potential clinical applications of 99mTc-RWY.

Integrin α6 associates with the survival and migration of breast cancer cells, which emerges as a predictor of reduced overall survival and worse prognosis. In this study, we developed an integrin α6-targeted radiotracer 99mTc-RWY for SPECT imaging of breast cancer. The safety, biodistribution and radiation dosimetry were studied in seven healthy volunteers, and the clinical potential of 99mTc-RWY was examined in two breast cancer patients. A single dose of 11.1 MBq/kg 99mTc-RWY was injected intravenously. Visual and semiquantitative methods were used to assess the SPECT/CT images. The routine Hematoxylin-Eosin (HE) staining and immunohistochemistry (IHC) staining were subsequently carried out to confirm the Integrin α6 expression of tumors.

Inclusion criteria:

• Healthy volunteers.
• Body mass index (BMI) at 19 to 25 [Body mass index = body weight (kg)/ height squared (m2)];
• Clinical laboratory tests (heart, liver, kidney, blood) indicators are in the normal range or abnormalities without clinical significance;
• Informed written consents were obtained from all 9 subjects before the procedure.
• Patients in suspicion of breast cancer by mammography or ultrasonography, and being able to provide basic information.

Exclution Criteria:

• The investigator judged that it is not suitable for clinical trials based on the overall situation of the volunteers and patients.