Mutational profile from cfDNA in this patient (ID9) revealed a series of mutations in the pretreatment sample. Interestingly, the FBXW7 mutation was not detected in the corresponding tumor biopsy. This mutation persisted despite clearance of other mutations from cfDNA and clinical remission. The patient relapsed in the CNS and the mutation was detected at a low level in cells from the cerebrospinal fluid. See Figure 7 in the article by Rossi et al that begins on page 1947.