Magnetic resonance imaging and histopathological characterization of prostate tumors in TRAMP mice as model for pre-clinical trials

BACKGROUND. The Transgenic Adenocarcinoma of Mouse Prostate (TRAMP) develops progressive forms of prostate cancer. Due to the lack of a validated non-invasive methodology, pathology has been so far the most common parameter evaluated in efficacy studies. METHODS. We studied by magnetic resonance imaging (MRI) 210 mice that were repeatedly measured up to 33 weeks of age in order to stage prostate tumors and follow pathological progression in single animals. A pre-clinical trial with doxorubicin was also performed. RESULTS. Progressive forms of cancer (well and poorly differentiated (PD) adenocarcinomas) were easily recognized on MR images and MRI findings were validated against histopathological analysis. Age at tumor onset was different for the two tumoral forms. Doxorubicin treatment caused a strong reduction in tumor volume. CONCLUSIONS. Prostate cancer in TRAMP mice is multifocal and heterogeneous: a noninvasive methodology such as MRI facilitates the rational design of translational pre-clinical trials in this widely used animal model.