BACKGROUND: Anaplastic Large Cell Lymphoma (ALCL) is a rare and aggressive T-cell lymphoma, classified into ALK-positive and ALK-negative subtypes, based on the presence of chromosomal translocations involving the ALK gene. The current standard of treatment for ALCL is polychemotherapy, with a high overall survival rate. However, a subset of patients does not respond to or develops resistance to these therapies, posing a serious challenge for clinicians. Recent targeted treatments such as ALK kinase inhibitors and anti-CD30 antibody-drug conjugates have shown promise but, for a fraction of patients, the prognosis is still unsatisfactory. METHODS: We investigated the genetic landscape of ALK + ALCL by whole-exome sequencing; recurring mutations were characterized in vitro and in vivo using transduced ALCL cellular models. RESULTS: Recurrent mutations in FAT family genes and the transcription factor RUNX1T1 were found. These mutations induced changes in ALCL cells morphology, growth, and migration, shedding light on potential factors contributing to treatment resistance. In particular, FAT4 silencing in ALCL cells activated the β-catenin and YAP1 pathways, which play crucial roles in tumor growth, and conferred resistance to chemotherapy. Furthermore, STAT1 and STAT3 were hyper-activated in these cells. Gene expression profiling showed global changes in pathways related to cell adhesion, cytoskeletal organization, and oncogenic signaling. Notably, FAT mutations associated with poor outcome in patients. CONCLUSIONS: These findings provide novel insights into the molecular portrait of ALCL, that could help improve treatment strategies and the prognosis for ALCL patients.

• MeSH
• Lymphoma, Large-Cell, Anaplastic * genetics   pathology   drug therapy   MeSH
• Phenotype MeSH
• Cadherins * genetics   MeSH
• Humans MeSH
• Mutation * MeSH
• Mice MeSH
• Cell Line, Tumor MeSH
• Prognosis MeSH
• Exome Sequencing MeSH
• Animals MeSH
• Check Tag
• Humans MeSH
• Mice MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Cadherins * MeSH

Anaplastic large-cell lymphoma (ALCL) is a T-cell malignancy predominantly driven by the oncogenic anaplastic lymphoma kinase (ALK), accounting for approximately 15% of all paediatric non-Hodgkin lymphoma. Patients with central nervous system (CNS) relapse are particularly difficult to treat with a 3-year overall survival of 49% and a median survival of 23.5 months. The second-generation ALK inhibitor brigatinib shows superior penetration of the blood-brain barrier unlike the first-generation drug crizotinib and has shown promising results in ALK+ non-small-cell lung cancer. However, the benefits of brigatinib in treating aggressive paediatric ALK+ ALCL are largely unknown. We established a patient-derived xenograft (PDX) resource from ALK+ ALCL patients at or before CNS relapse serving as models to facilitate the development of future therapies. We show in vivo that brigatinib is effective in inducing the remission of PDX models of crizotinib-resistant (ALK C1156Y, TP53 loss) ALCL and furthermore that it is superior to crizotinib as a second-line approach to the treatment of a standard chemotherapy relapsed/refractory ALCL PDX pointing to brigatinib as a future therapeutic option.

• Keywords
• ALCL, PDX, brigatinib, crizotinib, tyrosine kinase inhibitors,
• MeSH
• Anaplastic Lymphoma Kinase MeSH
• Lymphoma, Large-Cell, Anaplastic * drug therapy   pathology   MeSH
• Child MeSH
• Heterografts MeSH
• Protein Kinase Inhibitors therapeutic use   MeSH
• Crizotinib pharmacology   therapeutic use   MeSH
• Humans MeSH
• Neoplasm Recurrence, Local drug therapy   MeSH
• Lung Neoplasms * drug therapy   MeSH
• Carcinoma, Non-Small-Cell Lung * MeSH
• Organophosphorus Compounds pharmacology   therapeutic use   MeSH
• Receptor Protein-Tyrosine Kinases therapeutic use   MeSH
• Check Tag
• Child MeSH
• Humans MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Anaplastic Lymphoma Kinase MeSH
• brigatinib MeSH Browser
• Protein Kinase Inhibitors MeSH
• Crizotinib MeSH
• Organophosphorus Compounds MeSH
• Receptor Protein-Tyrosine Kinases MeSH

Non-Hodgkin lymphomas (NHL) represent the most common hematologic malignancies. Patient-derived xenografts (PDXs) are used for various aspects of translational research including preclinical in vivo validation of experimental treatment approaches. While it was repeatedly demonstrated that PDXs keep majority of somatic mutations with the primary lymphoma samples, from which they were derived, the composition of PDX tumor microenvironment (TME) has not been extensively studied. We carried out a comparative genetic and histopathological study of 15 PDX models derived from patients with various types of NHL including diffuse large B-cell lymphoma (DLBCL; n = 7), Burkitt lymphoma (BL; n = 1), mantle cell lymphoma (MCL; n = 2), and peripheral T-cell lymphomas (PTCL; n = 5). Whole exome sequencing (WES) of the PDXs and primary lymphoma cells was implemented in 13 out of 15 cases with available DNA samples. Standard immunohistochemistry (IHC) was used to analyze the composition of PDX TME. WES data confirmed that PDXs maintained the genetic heterogeneity with the original primary lymphoma cells. In contrast, IHC analysis revealed the following recurrently observed alterations in the composition of PDX tumors: more blastoid lymphoma cell morphology, increased proliferation rate, lack of non-malignant cellular components including T cells and (human or murine) macrophages, and significantly lower intratumoral microvessel density and microvessel area composed of murine vessels. In addition, PDX tumors derived from T-NHL displayed additional differences compared to the primary lymphoma samples including markedly lower desmoplasia (i.e., the extent of both reticular and collagen fibrosis), loss of expression of cytotoxic granules (i.e., perforin, TIA, granzyme B), or loss of expression of T-cell specific antigens (i.e., CD3, CD4, CD8). Our data suggest that despite keeping the same genetic profiles, PDX models of aggressive NHL do not recapitulate the microenvironmental heterogeneity of the original lymphomas. These findings have implications on the relevance of PDX models in the context of preclinical research.

• MeSH
• Lymphoma, Large B-Cell, Diffuse * MeSH
• Adult MeSH
• Heterografts MeSH
• Humans MeSH
• Disease Models, Animal MeSH
• Mice MeSH
• Tumor Microenvironment MeSH
• Antineoplastic Agents * MeSH
• Animals MeSH
• Check Tag
• Adult MeSH
• Humans MeSH
• Mice MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Antineoplastic Agents * MeSH

Non-Hodgkin lymphoma (NHL) is the third most common malignancy diagnosed in children. The vast majority of paediatric NHL are either Burkitt lymphoma (BL), diffuse large B-cell lymphoma (DLBCL), anaplastic large cell lymphoma (ALCL), or lymphoblastic lymphoma (LL). Multi-agent chemotherapy is used to treat all of these types of NHL, and survival is over 90% but the chemotherapy regimens are intensive, and outcomes are generally poor if relapse occurs. Therefore, targeted therapies are of interest as potential solutions to these problems. However, the major problem with all targeted agents is the development of resistance. Mechanisms of resistance are not well understood, but increased knowledge will facilitate optimal management strategies through improving our understanding of when to select each targeted agent, and when a combinatorial approach may be helpful. This review summarises currently available knowledge regarding resistance to targeted therapies used in paediatric anaplastic lymphoma kinase (ALK)-positive ALCL. Specifically, we outline where gaps in knowledge exist, and further investigation is required in order to find a solution to the clinical problem of drug resistance in ALCL.

• Keywords
• anaplastic large cell lymphoma, chemotherapy, nucleophosmin1-anaplastic lymphoma kinase, paediatric cancer, resistance,
• Publication type
• Journal Article MeSH
• Review MeSH

• MeSH
• Lymphoma, Large-Cell, Anaplastic genetics   pathology   MeSH
• Child MeSH
• Adult MeSH
• Middle Aged MeSH
• Humans MeSH
• Adolescent MeSH
• Young Adult MeSH
• Mutation genetics   MeSH
• Tumor Suppressor Protein p53 genetics   MeSH
• Child, Preschool MeSH
• Prognosis MeSH
• Aged, 80 and over MeSH
• Aged MeSH
• STAT3 Transcription Factor genetics   MeSH
• Check Tag
• Child MeSH
• Adult MeSH
• Middle Aged MeSH
• Humans MeSH
• Adolescent MeSH
• Young Adult MeSH
• Male MeSH
• Child, Preschool MeSH
• Aged, 80 and over MeSH
• Aged MeSH
• Female MeSH
• Publication type
• Letter MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Tumor Suppressor Protein p53 MeSH
• STAT3 protein, human MeSH Browser
• TP53 protein, human MeSH Browser
• STAT3 Transcription Factor MeSH