Multiomics of three distinct hematological malignancies in a patient reveals their common origin from clonal hematopoietic stem cells

Concomitant multiple hematological malignancies are rare and challenging to diagnose. They represent a unique model to explore the multistep process of oncogenesis. Here, we report the unique case of 62 years-old man with cardiac tamponade as first manifestation of ALK negative anaplastic large T-cell lymphoma (ALK- ALCL). Following chemotherapy, he showed one year later ALK- ALCL concurrent with diffuse large B-cell lymphoma (DLBCL-NOS) and acute monoblastic leukemia (AML-M5) in a single excisional lymph node. Clinical, pathological and multiomics data (whole exome and targeted deep sequencing, spatial transcriptomics) were analyzed. Two somatic TET2 gene mutations at high allele burden were shared by all three neoplasms, uninvolved bone marrow and CD34+ hematopoietic stem and progenitor cells (HSPCs). Secondary hits characterized each malignancy. ALK- ALCL (pericardial and nodal) showed TP53 and LYN deleterious mutations, DLBCL-NOS disclosed KRAS, STAT6, CREBBP and ATM alterations and AML-M5 had JAK3, PPM1D, NF1 and KMT2D mutations and a complex karyotype. Furthermore we demonstrated that spatial transcriptomics can identify the specific signatures of the three neoplasms. Two TET2 mutations at high allele burden in CD34+HSPCs conferred the favorable soil and the genotoxic stress from chemotherapy likely contributed to multiple hematological malignancies oncogenesis. Our case confirms the pathogenetic link between clonal hematopoiesis and cytotoxic T-cell lymphoma, so far only suspected. Most importantly, this is the first study to document the oncogenic phylogeny of concurrent T-, B-, and myeloid neoplasms from CD34+ HSPCs clone(s) in a single specimen.