Animal models and molecular imaging tools to investigate lymph node metastases.

Lymph node metastasis is a strong predictor of poor outcome in cancer patients. Animal studies of lymph node metastasis are constrained by difficulties in the establishment of appropriate animal models, limitations in the noninvasive monitoring of lymph node metastasis progression, and challenges in the pathologic confirmation of lymph node metastases. In this comprehensive review, we summarize available preclinical animal cancer models for noninvasive imaging and identification of lymph node metastases of non-hematogenous cancers. Furthermore, we discuss the strengths and weaknesses of common noninvasive imaging modalities used to identify tumor-bearing lymph nodes and provide guidelines for their pathological confirmation.