Despite the availability of PARP inhibitors for cancer therapy, a biomarker to clearly stratify patients for selection of this treatment remains lacking. Here we describe a radiotracer-based method that addresses this issue, using the novel compound [125I]KX1 as a PARP-1–selective radiotracer that can accurately measure PARP-1 expression in vitro and in vivo. The pharmacologic properties of the PARP radiotracer [125I]KX1 was characterized in multiple cell lines where single-agent sensitivity was correlated with [125I]KX1 binding to PARP-1. In vivo evaluation of [125I]KX1 verified in vitro results, validating PARP radiotracers to define PARP-1 enzyme expression as an in vivo biomarker. Notably, PARP-1 expression as quantified by [125I]KX1 correlated positively with the cytotoxic sensitivity of cell lines evaluated with PARP inhibitors. Overall, our results defined a novel technology with the potential to serve as a companion diagnostic to identify patients most likely to respond therapeutically to a PARP inhibitor.

Posterior reversible encephalopathy syndrome (PRES) represents a unique clinical entity with non-specific clinical symptoms and unique neuroradiological findings. This syndrome may present with a broad range of clinical symptoms from headache and visual disturbances to seizure and altered mentation. Typical imaging findings include posterior-circulation predominant vasogenic edema. Although there are many well-documented diseases associated with PRES, the exact pathophysiologic mechanism has yet to be fully elucidated. Generally accepted theories revolve around disruption of the blood-brain barrier secondary to elevated intracranial pressures or endothelial injury. In this article, we will review the clinical, typical, and atypical radiological features of PRES, as well as the most common theories behind the pathophysiology of PRES. Additionally, we will discuss some of the treatment strategies for PRES related to the underlying disease state.

This review explores recent work directed toward the development of nanoparticles (NPs) for multimodality cancer imaging and targeted cancer therapy. In the growing era of precision medicine, theranostics, or the combined use of targeted molecular probes in diagnosing and treating diseases is playing a particularly powerful role. There is a growing interest, particularly over the past few decades, in the use of NPs as theranostic tools due to their excellent performance in receptor target specificity and reduction in off-target effects when used as therapeutic agents. This review discusses recent advances, as well as the advantages and challenges of the application of NPs in cancer imaging and therapy.

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