Novel Strategies for Breast Cancer Imaging: New Imaging Agents to Guide Treatment.

The development of molecular therapies for cancer treatment has created a need to image biochemical and molecular processes to appropriately select tumors that express the drug target, thereby predicting a positive response to therapy. Biomarker-driven molecular imaging is complementary to pathologic analysis and offers a more direct measure of drug efficacy and treatment response, potentially providing early insight into therapeutic futility and allowing response-adapted treatment strategies. Imaging also allows a unique means of assessing the heterogeneity of both intra- and intertumoral targets as well as a mixed response to therapy; this information is important in the setting of metastatic disease. Here we review the development of novel molecular imaging probes and combinations of probes to guide therapy for two new targets and associated therapeutic agents: cyclin-dependent kinase inhibitors and poly(adenosine diphosphate-ribose) polymerase inhibitors.