Functional and molecular magnetic resonance imaging of preclinical cancer models in drug discovery and development

Cancer cells exhibit typical characteristics (outlined in Table 13.1), which, although individually not dangerous, collectively make the disease life threatening and difficult to treat. Magnetic resonance (MR) methods can be applied to study several of these characteristics and their response to therapy, in the context of drug discovery and development. As a disease, cancer exhibits different levels of malignancy, starting with low grade tumors which tend to resemble normal cells and grow slowly, to high grade poorly differentiated or undifferentiated tumors, which do not resemble the tissue of origin [1], and are aggressive and grow rapidly. One of the challenges facing MR methods is to identify parameters, which closely reflect the grade or aggressiveness of tumors and the danger they pose. The paradigm shift of viewing cancer as a chronic disease, and the development of agents which control the tumor through therapies such as antiangiogenic drugs, differentiating agents, or specific molecular targeting, has resulted in a concurrent and urgent requirement to detect tumor response.