MLL-SEPT6 Positive Acute Myeloid Leukemia Patients Often Co-occur With NRAS Mutations?

Abstract BackgroundThe MLL-SEPT6 fusion gene is a relatively rare genetic event in leukemia. Its clinical characteristics, prognosis, especially the profile of co-occurring gene mutations remain unclear. MethodsWe retrospectively analyzed four rare leukemia cases carrying MLL-SEPT6 in our hospital from laboratory examination, diagnosis, treatment and prognosis, and provided a comprehensive and detailed description on clinical profile of MLL-SEPT6-positive AML patients in the literature. ResultsAll the four patients were diagnosed with acute myeloid leukemia (AML) and harbored X chromosome and 11 chromosome rearrangements. Three of four cases occurred NRAS mutation while the rest one with congenital AML did not. Of the four cases, one developed drug-resistant, one suffered relapse after bone marrow transplantation (BMT) and one died. Combined with other cases reported in literatures, we found that of all patients diagnosed with AML, 90.9% were children (≤ 9 years old) and 54.5% were infants (≤1 year old). The survival time between infant group (≤1 year old) and pediatric group (>1 and <18 years old), patients that received BMT and that received chemotherapy alone did not show significant differences (P>0.05). ConclusionsMLL-SEPT6 was more commonly observed in pediatric AML patients, some of which may co-occur with NRAS mutations. The prognosis was inconclusive and may not be related to age or BMT. More information needs to be accumulated and summarized from additional cases to confirm the underlying connection between NRAS mutations and MLL-SEPT6 in order to better understand the profile in MLL-SEPT6-positive AML.