EVALUATION OF THE HER2/NEU EXPRESSION IN THE TISSUE OF METASTATIC AXILLARY LYMPH NODES IN BREAST CANCER PATIENTS USING THE [99mTs]TC-(HE)3-G3

Anatomic visualization and molecular typing of metastatic regional lymph nodes in breast cancer patients are a serious clinical challenge in modern oncology. According to the results of previous studies, [99mTc]Tc-(HE)3-G3 has proven to be a promising diagnostic agent in differentiating the HER2/neu receptor status in primary breast tumors (<i>p</i> < 0.05, Mann-Whitney test). In this regard, the purpose of this study is to explore the possibilities of using [99mTc]Tc-(HE)3-G3 to determine the HER2/neu receptor status in the metastatic axillary lymph nodes (mALNs) of breast cancer patients. The study was conducted using clinical material from 20 breast cancer patients (T2-4N1-3M0-1) before systemic therapy (10 patients with positive and 10 patients with negative HER2/neu expression in mALNs) who underwent SPECT/CT scan 4 h after the administration of [99mTc]Tc-(HE)3-G3. Morphological and immunohistochemical studies of mALNs with assessment of the HER2/neu status were performed on all patients. We found that mALN-to-background and mALN-to-latissimus dorsi muscle ratios for [99mTc]Tc-(HE)3-G3 uptake 4 h after its administration may be used for typing of the HER2/neu status in mALNs of breast cancer patients (<i>p</i> < 0.05, Mann-Whitney test). In that case, sensitivity and specificity for the mALN-to-background ratio were identical at 80%, with the threshold value being > 12.25.