TP53 mutations are common in mantle cell lymphoma, including the indolent leukemic non-nodal variant

Introduction: Mantle cell lymphoma (MCL)is an aggressive B-cell neoplasm, but clinically indolent subtypes are also recognized. Data on the utility of mutation profiling in the context of routine workup and its role in risk-stratification of MCL patients are limited. In this study, we describe the mutational landscape and clinicopathologic correlates of a series of MCL cases at a single-institution setting. Methods: Samples from 26 patients with MCL were evaluated by NGS using DNA extracted from peripheral blood (PB)or bone marrow (BM). Evaluation of extent of PB or BM involvement was performed using flow cytometry immunophenotyping. Results: The study group included 17 (65%)men and 9 (35%)women with a median age of 65 years (range, 50–94). Twenty-one (81%)patients had nodal MCL (N-MCL)and 5 (19%)had the “leukemic variant” (L-MCL). Mutated genesincluded TP53 (35%), ATM (27%), CARD11 (10%); and FBXW7, NOTCH1, SPEN, BIRC3 (~5% each). Most mutations were clonal in nature. Ten unique TP53 mutations were identified in 9 samples, including 3 L-MCL cases. There was no difference in the frequency of TP53 mutations between L-MCL and N-MCL groups (p = 0.3), but TP53 mutations were subclonal in 2/3 L-MCL cases. Identification of clonal TP53 alterations in L-MCL patients prompted initiation of therapy despite low tumor burden. Conclusions: TP53 is commonly mutated in MCL. TP53 mutations may be clonal or subclonal. Seemingly indolent L-MCL may harbor subclonal TP53 mutations which may serve as a useful biomarker for prognostication, therapeutic planning, follow-up monitoring, and early detection of clonal expansion.