PPM1D Mutation as a Distinct Feature of Myeloid Neoplasms in B-Cell Non-Hodgkin Lymphoma Patients: A Retrospective Analysis

Background/Objectives: Myeloid neoplasms are the most common secondary blood cancer in B-cell non-Hodgkin lymphoma (BNHL) patients treated with cytotoxic therapies. We aimed to characterize the genetic and clinicopathologic features of myeloid neoplasms arising after B-cell non-Hodgkin lymphoma (MN-BNHL) by comparing their features with myeloid neoplasms developing after solid cancer (MN-SC). Methods: We retrospectively analyzed the clinicopathologic and genetic data of myeloid neoplasm patients diagnosed between 2008 and 2023, categorized as MN-BNHL or MN-SC. Further NGS analysis was performed on available bone marrow samples with missing genetic data. The genetic profiles of myeloid neoplasms between BNHL and solid cancer groups were compared. Results: Sixteen patients developed MN-BNHL. Among the 11 MN-BNHL patients undergoing NGS, all harbored tier 1 mutations. PPM1D mutations (PPM1Dms) were most frequent (73%), followed by DNMT3A (46%) and TP53 (36%). PPM1Dms were significantly more prevalent than in MN-SC (n = 21), where TP53 mutations were most common (64%) (p < 0.001). PPM1Dms often co-occurred with DNMT3A. They were associated with prior radioimmunotherapy (relative risk (RR): 3.3 and RR 3.57). MN-BNHL patients with PPM1Dms exhibited improved survival compared to those without (p = 0.0376), but this benefit was negated by the presence of TP53 mutations (p = 0.0049). Conclusions: PPM1Dms are a prominent genetic feature in MN-BNHL, suggesting a distinct role in its development compared to MN-SC. Further investigation is needed to elucidate the precise contribution of PPM1D and its interaction with other mutations in BNHL-related myeloid neoplasm development and prognosis.