Phylogenetic trees. Phylogenetic trees from 4 different patients with relapsed PCNSL. (A-C) Comparison of the primary tumor with the relapsed specimen: primary and brain relapse (A), primary and systemic relapse (B), and primary and testicular relapse (C). (D) Comparison between simultaneous occurrence of brain and skin lymphoma. The width of each line corresponds to the CCF. Subpopulations (CCF <1) are labeled at the end of each line. The length of the line corresponds to the number of mutations that are present. Relevant mutations are indicated on each branch. Gray, shared; blue, private to primary tumor specimen in the CNS; purple, private to the relapsed or extracranial tumor specimen.