In vivo detection of breast cancer liver metastases in humanized tumour mice using tumour specific contrast agent BR55®

Abstract

OBJECTIVE: To investigate the diagnostic accuracy of high-resolution ultrasound (HRU) for the detection of hepatic metastases of breast cancer in a humanized tumour mouse (HTM) using clinical standard technology. In addition, the efficiency of standard contrast-enhanced ultrasound (CEUS) [microbubbles of sulphur hexafluoride] and CEUS using a novel VEGFR2-targeted contrast agent [BR55®] was examined. METHODS: A total of 14 HTM were sonographically examined twice. In addition to a human immune system, the animals developed hepatic tumour lesions after intrahepatic injection of BT-474 breast cancer cells. Digital cine loops from the arterial phase (15–35 sec), the portal venous phase (35–90 sec) and the late phase (3–15 min) of the entire liver were analysed. Data were correlated to histopathology. RESULTS: After 9 months, half of the mice (7/14) revealed the development of hepatic breast cancer metastases. The detection limit was 1 mm tumour diameter. In particular, the use of targeted contrast media reduced the needed tumour diameter and helped to precisely classify tumour tissue. In 93% (13/14), the findings of ultrasound could be approved by histological examination by the pathologist. CONCLUSIONS: This study in HTM demonstrated the high feasibility of tumour specific contrast media and standard HRU contrast agents to detect early liver metastases.