68GA-FAPI PET/CT IN DIAGNOSIS OF THE BREAST CANCER DEPENDING ON THE MOLECULAR SUBTYPES AND EXPRESSION STATUS OF HUMAN...

This study evaluates the diagnostic potential of 68Ga-FAPI PET/CT in women with newly diagnosed breast cancer (BC), with an emphasis on molecular subtypes and HER2/neu expression status. A total of 34 patients (median age: 55.5 years; range: 26-80) with histologically confirmed invasive BC underwent 68Ga-FAPI PET/CT prior to initiating treatment. Tumors were classified according to immunohistochemical markers (ER, PR, HER2/neu, Ki-67) into Luminal A, Luminal B (HER2-negative and HER2-positive), and triple-negative subtypes. A total of 46 malignant lesions were identified, including multicentric tumors in 9 patients. The highest FAPI uptake (SUVmax and TBR) was observed in HER2-positive tumors, particularly Luminal B HER2-positive subtypes. Statistically significant differences in FAPI uptake and TBR were found between tumors with HER2 overexpression and those with HER2-zero expression (p = 0.015). The study demonstrates that 68Ga-FAPI PET/CT may enhance diagnostic accuracy in aggressive BC phenotypes, particularly HER2-overexpressing tumors, and could serve as a valuable complementary imaging modality for staging and treatment planning.