VPAC1 receptors for imaging breast cancer: a feasibility study.
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ABSTRACT: VPAC1 encodes G-protein-coupled receptors expressed on all breast cancer (BC) cells at the onset of the disease, but not on benign lesions. Our extensive preclinical studies have shown that (64)Cu-TP3805 has a high affinity for VPAC1, is stable in vivo, and has the ability to distinguish spontaneously grown malignant BC masses from benign lesions. Our long-term goal is to develop (64)Cu-TP3805 as an agent to perform in vivo histology, to distinguish malignant lesions from benign masses noninvasively and thereby avoid patient morbidity and the excess economic costs of benign biopsies.(18)F-FDG obtained commercially served as a control. (64)Cu-TP3805 was prepared using a sterile kit containing 20 μg of TP3805. Radiochemical purity and sterility were examined. Nineteen consenting women with histologically proven BC were given 370 MBq of (18)F-FDG. One hour later, 6 of these patients were imaged with PET/CT and 13 with positron emission mammography (PEM). Two to 7 d later, 6 PET/CT patients received 111 MBq (± 10%) (n = 2), 127 MBq (± 10%) (n = 2), or 148 MBq (± 10%) (n = 2) of (64)Cu-TP3805 and were imaged 2 and 4 h later. Thirteen PEM patients received 148 MBq (± 10%) of (64)Cu-TP3805 and were imaged 15 min, 1 h, 2 h, and 4 h later. Standardized uptake value (SUV) was calculated for PET/CT patients, and PUV/BGV (PEM uptake value/background value) was calculated for PEM patients. Tumor volume was also calculated.The radiochemical purity of (64)Cu-TP3805 was 97% ± 2%, and specific activity was 44.4 GBq (1.2 Ci)/μmol. In 19 patients, a total of 24 lesions were imaged (15 invasive ductal carcinoma, 1 high-grade mammary carcinoma, 3 lobular carcinoma, 1 invasive papilloma, and 4 sentinel lymph nodes). All lesions were unequivocally detected by (64)Cu-TP3805 and by (18)F-FDG. The average tumor volume as determined by PET/CT with (64)Cu-TP3805 was 90.6% ± 16.1% of that with (18)F-FDG PET/CT, and the average SUV was 92% ± 26.4% of that with (18)F-FDG. For PEM, the tumor volume with (64)Cu-TP3805 was 113% ± 37% of that with (18)F-FDG and the PUV/BGV ratio was 97.7% ± 24.5% of that with (18)F-FDG.(64)Cu-TP3805 is worthy of further investigation in patients requiring biopsy of suggestive imaging findings, to further evaluate its ability to distinguish malignant lesions from benign masses noninvasively.
SUBMITTER: Thakur ML
PROVIDER: S-EPMC5506835 | biostudies-other | 2013 Jul
REPOSITORIES: biostudies-other
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