99mTc-DARPinG3-based HER2 Expression Molecular Imaging in HER2-positive Breast Cancer During Chemo+Targeted Therapy

Inclusion Criteria: 1. Subject is \> 18 years of age; 2. Diagnosis of primary breast cancer with tumour size ≥ 20 mm and with possible lymph node metastases; 3. Availability of results from HER2 status previously determined on material from the primary tumor: HER2-positive, defined as a DAKO HercepTest™ score of 3+ or FISH positive; 4. In neoadjuvant all patients should receive standard chemo-targeted therapy according to the DCH+P (docetaxel + carboplatin+ trastuzumab+ pertuzumab) scheme; 5. Injection of 99mTc-DARPinG3 at the dosage 3000 µg before and after 2 and 4 courses of chemo+targeted therapy in each HER2-positive breast cancer patient; 6. Biopsies should be performed in all patients HER2-positive breast cancer patients before and after 2 and 4 courses of chemo+targeted therapy with evaluation of HER2 expression; 7. Hematological, liver and renal function test results within the following limits: * White blood cell count: \> 2.0 x 109/L * Hemoglobin: \> 80 g/L * Platelets: \> 50.0 x 109/L * ALT, ALP, AST: =\< 5.0 times Upper Limit of Normal * Bilirubin =\< 2.0 times Upper Limit of Normal * Serum creatinine: Within Normal Limits 8. A negative pregnancy test for all patients of childbearing potential. Sexually active women of childbearing potential participating in the study must use a medically acceptable form of contraception for at least 30 days after study termination; 9. Subject is capable to undergo the diagnostic investigations to be performed in the study; 10. Informed consent Exclusion Criteria: 1. Second, non-breast malignancy 2. Active current autoimmune disease or history of autoimmune disease 3. Active infection or history of severe infection within the previous 3 months (if clinically relevant at screening) 4. Known HIV positive or chronically active hepatitis B or C 4. Administration of other investigational medicinal product within 30 days of screening 5. Ongoing toxicity \> grade 2 from previous standard or investigational therapies, according to US National Cancer Institute's