ALK and diffuse large B-cell lymphoma of the central nervous system: When all lymphomas were arranged in the order of median value of the number of SNV/Indel mutations, primary mediastinal large B-cell lymphoma (PMLBL) (median: 32) ranked first, followed by CNS DLBCL (median: 30), DLBCL NOS (median: 23), and anaplastic large cell lymphoma, ALK-negative (ALCL, ALK-) (median: 23) (Fig. 2).