ABSTRACT
Systemic Mastocytosis is a clonal proliferation of mast cells; in a significant fraction of cases it is associated with another concurrent hematological neoplasm. Molecular analysis of KIT mutations and other associated genetic alterations suggest a common origin in the stem cell compartment. Mast cell infiltration patterns in bone marrow biopsy may be subtle in cases associated with t (8;21) AML. Here we report three cases of clonally related SM-AHN, two cases with SM-CMML and one case with SM- t (8;21) AML. We describe in detail the bone marrow infiltration pattern at diagnosis and during the course of treatment with allogeneic stem cell transplant and novel TK inhibitors, showing the unique dynamics of mast cell clearance after therapy.(AU)
La mastocitosis sistémica es una proliferación clonal de mastocitos que puede asociarse con otra neoplasia hematológica concurrente en una fracción significativa de los casos. El análisis molecular de mutaciones de KIT y otras alteraciones genéticas asociadas indican un origen común en el compartimento de células madre. Los patrones de infiltración de mastocitos en la biopsia de médula ósea pueden ser sutiles en los casos asociados con AML t (8; 21). Aquí se describen 3 casos de MS-NHA, 2 casos con MS-LMMC y un caso con MS-t (8; 21) LMA. Describimos en detalle el patrón de infiltración de la médula ósea en el momento del diagnóstico y durante el curso del tratamiento con alotrasplante de células madre y nuevos inhibidores de TK, mostrando la dinámica de la depuración de mastocitos después de la terapia.(AU)
Subject(s)
Humans , Mastocytosis, Systemic , Hematologic Neoplasms , Bone Marrow Transplantation , Mast Cells , Leukemia, Myeloid, AcuteABSTRACT
Plasmablastic lymphoma is an uncommon aggressive non-Hodgkin B-cell lymphoma type defined as a high-grade large B-cell neoplasm with plasma cell phenotype. Genetic alterations in MYC have been found in a proportion (~60%) of plasmablastic lymphoma cases and lead to MYC-protein overexpression. Here, we performed a genetic and expression profile of 36 plasmablastic lymphoma cases and demonstrate that MYC overexpression is not restricted to MYC-translocated (46%) or MYC-amplified cases (11%). Furthermore, we demonstrate that recurrent somatic mutations in PRDM1 are found in 50% of plasmablastic lymphoma cases (8 of 16 cases evaluated). These mutations target critical functional domains (PR motif, proline rich domain, acidic region, and DNA-binding Zn-finger domain) involved in the regulation of different targets such as MYC. Furthermore, these mutations are found frequently in association with MYC translocations (5 out of 9, 56% of cases with MYC translocations were PRDM1-mutated), but not restricted to those cases, and lead to expression of an impaired PRDM1/Blimp1α protein. Our data suggest that PRDM1 mutations in plasmablastic lymphoma do not impair terminal B-cell differentiation, but contribute to the oncogenicity of MYC, usually disregulated by MYC translocation or MYC amplification. In conclusion, aberrant coexpression of MYC and PRDM1/Blimp1α owing to genetic changes is responsible for the phenotype of plasmablastic lymphoma cases.
