RT Journal Article SR Electronic T1 Patterns of αvβ3 Expression in Primary and Metastatic Human Breast Cancer as Shown by 18F-Galacto-RGD PET JF Journal of Nuclear Medicine JO J Nucl Med FD Society of Nuclear Medicine SP 255 OP 259 DO 10.2967/jnumed.107.045526 VO 49 IS 2 A1 Beer, Ambros J. A1 Niemeyer, Markus A1 Carlsen, Janette A1 Sarbia, Mario A1 Nährig, Jörg A1 Watzlowik, Petra A1 Wester, Hans-Jürgen A1 Harbeck, Nadia A1 Schwaiger, Markus YR 2008 UL http://jnm.snmjournals.org/content/49/2/255.abstract AB The integrin αvβ3 is a key player in angiogenesis and metastasis. Our aim was to study the uptake patterns of the αvβ3-selective PET tracer 18F-galacto-RGD in invasive ductal breast cancer. Methods: Sixteen patients with primary (n = 12) or metastasized breast cancer (n = 4) were examined with 18F-galacto-RGD PET. Standardized uptake values (SUVs) were derived by region-of-interest analysis, and immunohistochemistry of αvβ3 expression was performed (n = 5). Results: 18F-Galacto-RGD PET identified all invasive carcinomas, with SUVs from 1.4 to 8.7 (mean ± SD, 3.6 ± 1.8; tumor-to-blood and tumor-to-muscle ratios, 2.7 ± 1.6 and 6.2 ± 2.2, respectively). Lymph-node metastases were detected in 3 of 8 patients (mean SUV, 3.3 ± 0.8). SUVs in distant metastases were heterogeneous (2.9 ± 1.4). Immunohistochemistry confirmed αvβ3 expression predominantly on microvessels (5/5) and, to a lesser extent, on tumor cells (3/5). Conclusion: Our results suggest generally elevated and highly variable αvβ3 expression in human breast cancer lesions. Consequently, further imaging studies with 18F-galacto-RGD PET in breast cancer patients for assessment of angiogenesis or planning of αvβ3-targeted therapies are promising.