Molecular genetics of childhood, adolescent and young adult non-Hodgkin lymphoma

Clinical and Molecular Properties of Human Immunodeficiency Virus-Related Diffuse Large B-Cell Lymphoma

Non-Hodgkin lymphoma is the most common malignancy affecting people living with HIV (PLWH). Among its several subtypes, diffuse large B-cell lymphoma (DLBCL) is an important manifestation within the HIV-infected compartment of the population. Since HIV is able to modulate B cells and promote lymphomagenesis through direct and indirect mechanisms, HIV-related DLBCL has specific characteristics. In this review, we address the clinical and molecular properties of DLBCL disease in the context of HIV infection, as well as the mechanisms by which HIV is able to modulate B lymphocytes and induce their transformation into lymphoma.

Constitutional 2p16.3 deletion including MSH6 and FBXO11 in a boy with developmental delay and diffuse large B-cell lymphoma

We describe a case of a boy with neurodevelopmental delay and a diffuse large B-cell lymphoma (DLBCL) in whom we discovered a germline de novo 2p16.3 deletion including MSH6 and part of the FBXO11 gene. A causative role for MSH6 in cancer development was excluded based on tumor characteristics. The constitutional FBXO11 deletion explains the neurodevelopmental delay in the patient. The FBXO11 protein is involved in BCL-6 ubiquitination and BCL-6 is required for the germinal center reaction resulting in B cell differentiation. Somatic loss of function alterations of FBXO11 result in BCL-6 overexpression which is a known driver in DLBCL. We therefore consider that a causative relationship between the germline FBXO11 deletion and the development of DLBCL in this boy is conceivable.

Personal tumor antigens in blood malignancies: genomics-directed identification and targeting

Hematological malignancies have long been at the forefront of the development of novel immune-based treatment strategies. The earliest successful efforts originated from the extensive body of work in the field of allogeneic hematopoietic stem cell transplantation. These efforts laid the foundation for the recent exciting era of cancer immunotherapy, which includes immune checkpoint blockade, personal neoantigen vaccines, and adoptive T cell transfer. At the heart of the specificity of these novel strategies is the recognition of target antigens presented by malignant cells to T cells. Here, we review the advances in systematic identification of minor histocompatibility antigens and neoantigens arising from personal somatic alterations or recurrent driver mutations. These exciting efforts pave the path for the implementation of personalized combinatorial cancer therapy.

Application of 2016 WHO classification in the diagnosis of paediatric high-grade MYC-negative mature B-cell lymphoma with Burkitt-like morphological features

AIMS

Historically, there has been no consensus on the diagnostic classification of high-grade B-cell lymphoma (HGBCL) with morphological features of Burkitt lymphoma (BL) but no MYC gene rearrangement (MYC-negative). The 2016 WHO classification of tumours of haematopoietic and lymphoid tissues has shed some light on this field with the modification of the grey-zone lymphoma with features intermediate between BL and diffuse large B-cell lymphoma, and the creation of several new entities. The aim of this study was to investigate how the revised WHO classification affects our practice in diagnosing these lymphomas in children.

METHODS

We retrospectively reviewed cases of mature HGBCL diagnosed at our hospital between 2015 and 2018.

RESULTS

Among 14 mature HGBCL cases with BL morphological features, 11 showed MYC rearrangement consistent with BL and 3 were MYC-negative. Two MYC-negative cases showed regions of 11q gain and loss by microarray consistent with Burkitt-like lymphoma with 11q aberration (BLL-11q). The third MYC-negative case showed diffuse and strong MUM1 expression, translocation involving 6p25 by chromosome analysis and IRF4 rearrangement by fluorescence in situ hybridisation analysis consistent with large B-cell lymphoma with IRF4 rearrangement (LBL-IRF4). All patients were treated according to applicable chemotherapeutic protocols and achieved remission.

CONCLUSIONS

BLL-11q and LBL-IRF4, two newly defined entities, should be considered in paediatric MYC-negative mature HGBCL cases. Accurate diagnosis needs careful histopathological examination and proper cytogenetic testing. Since they have unique cytogenetic features, specific treatments for them may emerge in the future. Therefore, accurate diagnosis based on the 2016 WHO classification is clinically significant.

Management of aggressive B-cell NHLs in the AYA population: an adult vs pediatric perspective

The adolescents and young adult (AYA) population represent a group wherein mature B-cell lymphomas constitute a significant proportion of the overall malignancies that occur. Among these are aggressive B-cell non-Hodgkin lymphomas (NHLs), which are predominantly diffuse large B-cell lymphoma, primary mediastinal B-cell lymphoma, and Burkitt lymphoma. For the most part, there is remarkable divide in how pediatric/adolescent patients (under the age of 18 years) with lymphoma are treated vs their young adult counterparts, and molecular data are lacking, especially in pediatric and AYA series. The outcome for AYA patients with cancers has historically been inferior to that of children or older adults, highlighting the necessity to focus on this population. This review discusses the pediatric vs adult perspective in terms of how these diseases are understood and approached and emphasizes the importance of collaborative efforts in both developing consensus for treatment of this population and planning future research endeavors.

Non-Hodgkin lymphoma across the pediatric and adolescent and young adult age spectrum

The non-Hodgkin lymphomas (NHLs) occurring in children and adolescents and young adults (AYA) are characterized by various age-related differences in tumor biology and survival. Children generally present with high-grade lymphomas, such as Burkitt lymphoma, diffuse large B-cell lymphoma, lymphoblastic lymphoma, and anaplastic large cell lymphoma, whereas low-grade histologic subtypes, such as follicular lymphoma, occur more frequently with increasing age. Treatment outcome for children with NHL is generally superior to that observed in adults. Factors contributing to this discrepancy include psychosocial factors, patient factors, and differences in tumor biology and therapy. These factors will be reviewed, with particular attention to the biological features of diffuse large B-cell lymphoma and anaplastic large cell lymphoma and corresponding therapeutic challenges. Novel targeting agents have been developed, which have been shown to be active in some patients. There is clearly a need for treatment protocols with eligibility criteria that cover the full span of the pediatric and AYA age range and that incorporate detailed molecular characterization of the tumors.