Figure 1. Effect of treatment on tumor-derived cfDNA in CSF.

Figure 1A. Patient #1 with melanoma. The level of mutant CSF cfDNA increased, consistent with worsening parenchymal leptomeningeal disease noted on MRI imaging. Figure 1B. Patient #10 with ECD. The level of tumor-derived CSF cfDNA decreased after initiation of vemurafenib, consistent with improvement in hypermetabolic activity on the known ECD-related bone lesions on PET imaging.