Somatic mutations in KMT2D and TET2 associated with worse prognosis in Epstein-Barr virus-associated T or natural killer-cell lymphoproliferative disorders.

Limited studies are available on the molecular pathogenesis of Epstein-Barr virus (EBV)-associated T or natural killer (NK) cell lymphoproliferative disorders (EBV+T/NK-LPD). In this retrospective study, we aim to elucidate the mutation profile of EBV+T/NK-LPD using capture-based targeted sequencing with a panel consisting of 64 lymphoma-related genes to identify driver genes associated with the development of EBV+T/NK-LPD. Targeted sequencing of 169 EBV+T/NK-LPD cases was performed using a panel of 64 lymphoma-related genes. Of the 169 EBV+T/NK-LPD cases, 123 had extra-nodal NK/T-cell lymphoma (ENKTL), 12 had aggressive NK-cell leukemia (ANKL) and 34 had EBV+ T-cell lymphoma of childhood (EBV+TL). The mutation profile revealed that all three subtypes of EBV+T/NK-LPDs had high mutation rates in STAT3, KMT2D, DDX3X, NOTCH1 and TET2. Target sequencing revealed that ENKTL, ANKL and EBV+TL were molecularly distinct, the mutation in nasal-ENKTL and extra-nasal-ENKTL are also different. Survival analysis revealed that ENKTL patients with gene mutations or loss of protein expression in either KMT2D or TET2 were significantly correlated with shorter overall survival. And although the EBV+TL and ANKL groups were too small to confirm survival disadvantage, the adverse prognosis trends of KMT2D or TET2 were showed in these two groups. We conclude that EBV+T/NK lymphoproliferative disorders have very distinct molecular profiles. Our findings also suggest the likely involvement of KMT2D and TET2 in the development of ENKTL, and possibly EBV+T/NK-LPDs in general.