Abstract

RATIONALE AND OBJECTIVES: Fibrin deposition has been indicated within the stroma of a majority of solid tumors. Here we assess the feasibility of using the established fibrin-specific probe EP-2104R for noninvasive imaging of fibrin in the context of breast cancer.
METHODS: EP-2104R, untargeted gadopentetate dimeglumine (Gd-DTPA), and a newly synthesized nonfibrin binding control linear peptide (CLP) were compared using steady-state and dynamic contrast-enhanced magnetic resonance imaging in a breast cancer xenograft mouse model at 9.4 T.
RESULTS: EP-2104R transiently enhanced both tumor core and tumor periphery, but only the enhancement in the tumor periphery persisted even 90 minutes after EP-2104R administration. However, untargeted Gd-DTPA and CLP are not retained in the tumor periphery. The half-life of EP-2104R in the tumor periphery (103 ± 18 minutes) is significantly longer (P CONCLUSIONS: The persistent enhancement observed in the tumor periphery with EP-2104R is likely a result of its fibrin-specific binding rather than its size and demonstrates the feasibility of EP-2104R for molecular imaging of fibrin in tumor stroma.