Novel combined variants of WT1 and TET2 in a refractory and recurrent AML patient

Somatic mutations in Wilms' tumor 1 (WT1) and tet methylcytosine dioxygenase 2 (TET2) genes were separately perceived as contributors to hematopoietic disorders and usually thought to have a mutually exclusive effect in acute myeloid leukemia (AML). However, we found novel WT1 and TET2 variants persistently co-existed in a refractory and recurrent AML patient with t(9;11)(p21.3;q23.3); KMT2A-MLLT3, and were only detectable genetic alteration in early recurrence. Hence, these two novel variants were further investigated in patient's family, and the potential effect on disease progression was evaluated at follow-up.

A 27-year-old male was diagnosed with AML, having t(9;11)(p21.3;q23.3); KMT2A-MLLT3, accompanied by WT1 (NM_024426.6:exon7:c.1109G>C:p.Arg370Pro) and TET2 (NM_001127208.3:exon11:c.5530G>A:p.Asp1844Asn) variants. After two cycles of induction chemotherapy, complete remission was achieved. A consolidation treatment was then completed. However, the evaluation of the bone marrow revealed that early recurrence, WT1 (p.Arg370Pro) and TET2 (p.Asp1844Asn) variants still detectable, instead of KMT2A-MLLT3. Subsequently, these two variants were proved to be germline variants, which inherited from father and mother respectively. And the patient's elder brother also carried TET2 (p.Asp1844Asn) variant. A sequential allogeneic HLA-matched sible hematopoietic stem cell transplantation (allo-HSCT) was carried out, and the donor is the patient's elder brother, the original two variants of patient were replaced by the donor-derived TET2 (p.Asp1844Asn) variant after allo-HSCT; the patient has remained in complete remission with regular follow-up.

In brief, it is firstly reported that WT1 p.Arg370Pro and TET2 p.Asp1844Asn variants co-existed in a refractory and recurrent AML patient by inheritance. These two variants of the patient were replaced with donor-derived TET2 p.Asp1844Asn after allo-HSCT, and the patient has remained in complete remission with regular follow-up.