14067 Background: In vivo imaging of avβ3 expression in tumors and tumor endothelial cells may be a useful biomarker of angiogenesis. [18F]AH11585 is a novel peptide containing an Arginine-Glycine-Aspartic Acid (RGD) motif that binds to avβ3 with high affinity designed for use in PET studies. Methods: 7 patients with metastatic breast cancer (aged 37–68 years) received intravenous injections of [18F]AH11585 and were scanned dynamically by PET over 61.5 mins. Radioactivity concentrations, derived from regions of interest placed on tumour and normal tissues, were analysed mathematically to determine the net irreversible uptake (Ki), fractional retention (FRT) and standardized uptake at 56.5min (SUV) of the radiotracer. Computed tomography (CT) was performed within 4 weeks of the scan. Results: Tumor lesions were clearly visible on PET images in 6/7 patients. In one patient with a palpable supraclavicular lymph node not visible on CT, we were unsure if a hyperintense region visible by PET was tumor. In total 18/19 tumor lesions were identified on both PET and corresponding CT images. Tumors in areas of low background were hyperintense (lung, bone, breast) whereas those in areas of high background were hypointense regions (liver). Tumors with central necrosis showed high uptake of [18F]AH11585 around the periphery only. Mathematical analysis demonstrated irreversible retention of [18F]AH11585 in tumors. [18F]AH11585-PET discriminated between non-liver lesions (n=10) and normal tissues: Ki (p=0.002), FRT (p=0.0039), SUV (p=0.002). Corresponding comparisons for liver lesions (n=8) were significant for FRT (p=0.0078) and SUV (p=0.0078) only. Conclusions: [18F]AH11585 PET is a promisng method for in vivo imaging of avβ3 integrin expression in metastatic breast cancer. No significant financial relationships to disclose.
Spatiotemporal assessment of spontaneous metastasis formation using multimodal in vivo imaging in HER2+ and triple negative metastatic breast cancer xenograft models in mice
