Mutational signature analysis. (A) A mutational signature was created for both de novo MDS and tMN patients, based on nondriver mutations that had been validated by TDS (n = 152 for tMN patients vs n = 145 for de novo MDS patients). (B) The distinctive mutational pattern, related to aging (signature 1: C > T@CpG) that was identified in both groups. (C) Representation of the number of mutations explained by signature 1 per individual patient. All other mutations are marked as “other” mutations.