In an integrated analysis of mutations and clinical outcomes, comprising 2,200 patients with TP53-mutated myelodysplastic syndrome (MDS) with excess blasts (EB) or TP53-mutated acute myeloid leukemia (AML), the authors state that mutant TP53 AML and MDS-EB “do not differ with respect to molecular characteristics and survival” and argue these entities should be considered a single molecular disease entity. In a commentary to the above paper, TP53 and the star-crossed lovers MDS and AML, John Welch, MD, PhD of Washington University School of Medicine writes, “As a junior Hematology/Oncology fellow, I was told there were two types of physicians: splitters and mergers. That is, clinicians either seek to diagnose increasingly homogenously narrow groups of patients based on increasingly refined, shared characteristics, or they seek to find broad, overarching patterns that unite diagnostic classifications. Hematologic malignancies have been fertile ground for the diagnostic splitters of the world. On the other hand, there have been some noteworthy exceptions. Sometimes it is a technological advance that allows for the synthesis of disparate diagnoses.”