Morphological and phenotypic features in pediatric large cell lymphoma and their correlation with ALK expression and the t(2;5)(p23;q35) translocation

Brentuximab vedotin use in pediatric anaplastic large cell lymphoma

Anaplastic large cell lymphoma (ALCL) is the most common type of mature T-cell non-Hodgkin lymphoma in children/adolescents. ALCL is characterized by expression of CD30 in the neoplastic lymphoid cells with frequent expression of anaplastic lymphoma kinase (ALK), especially within the pediatric population. Despite multiple efforts to optimize the use of conventional chemotherapy, outcomes in children, adolescents, and adults with ALCL remain suboptimal. Thus, there is a need to improve survival for those with high-risk disease and decrease therapy exposures and toxicities for those with low-risk disease. Targeted therapies, such as the anti-CD30 antibody-drug conjugate, brentuximab vedotin, are new important therapeutic options. Phase I and II studies in adults with relapsed/refractory CD30⁺ lymphomas, including ALCL, demonstrated the safety and efficacy of brentuximab vedotin, leading to FDA approval for relapsed/refractory ALCL in adults and successful incorporation into frontline therapies. Clinical trials in the pediatric population demonstrated similar results in those with relapsed/refractory ALCL. Incorporation of brentuximab vedotin into upfront therapy for children and adolescents with ALCL showed that this novel combination therapy has clinical advantages in comparison to conventional agents alone. Brentuximab vedotin is well-tolerated in both the pediatric and adult populations, even when used in combination with conventional agents. Brentuximab vedotin is an ideal agent to treat ALCL with excellent targeted activity and limited toxicity. Future studies are needed to identify how brentuximab vedotin should be utilized when combined with immunotherapy or other targeted agents (e.g., ALK inhibitors) in both the upfront and relapsed/refractory setting.

Childhood anaplastic large cell lymphoma has a high incidence of ALK gene rearrangement as determined by immunohistochemical staining and fluorescent in situ hybridisation: a genetic and pathological correlation

Anaplastic large cell lymphoma (ALCL) comprises 10-15% of childhood non-Hodgkin lymphomas (NHL). Systemic ALCL is highly associated with anaplastic lymphoma kinase (ALK) gene translocations with over-expression of ALK protein. We studied ALK rearrangements using fluorescence in situ hybridisation (FISH) and ALK immunohistochemical staining in 43 paediatric systemic ALCLs. FISH (performed on 35 cases) identified a translocation in 29 cases (83%). Immunohistochemistry identified ALK over-expression in 42/43 cases (97%) with the single ALK-negative case demonstrating an ALK rearrangement by FISH, indicating 100% incidence of ALK translocations.

High expression of calcium-binding proteins, S100A10, S100A11 and CALM2 in anaplastic large cell lymphoma

Anaplastic large cell lymphomas (ALCL) are characterised by the presence of CD30-positive large cells, which usually are of T-cell type. Based on the presence or absence of translocations involving the anaplastic lymphoma kinase (ALK) locus, ALCL cases can be divided into two groups. To gain more insight in the biology of ALCL, we applied serial analysis of gene expression (SAGE) on the Karpas299 cell line and identified 25 up- and 19 downregulated genes. Comparison of the differentially expressed genes with DNA copy number changes in Karpas299 revealed that two overexpressed genes, S100A10 and S100A11, were located in an amplicon suggesting that the increased mRNA levels were caused by DNA amplification. Quantitative reverse transcription polymerase chain reaction on 5 ALCL cell lines and 12 ALCL tissues confirmed the SAGE data for 13 out of 14 up- and one out of four downregulated genes. Immunohistochemical staining confirmed the presence of S100A10, a calcium-binding protein, in three out of five ALK+ and all 7 ALK- ALCL cases. S100A11 staining was confirmed in all ALK+ and six of seven ALK- ALCL cases. Three of the upregulated genes represented calcium-binding proteins, which suggest that altered intracellular signaling might be associated with the oncogenesis of ALCL.

Childhood and adolescent non-Hodgkin lymphoma: new insights in biology and critical challenges for the future

Pediatric non-Hodgkin lymphoma (NHL) is a common and fascinating group of diseases with distinctive underlying genetic events that characterize the major histologic subtypes: diffuse large B-cell lymphoma, Burkitt lymphoma, anaplastic large cell lymphoma and lymphoblastic lymphoma. With systematic improvements in therapy over recent decades, the vast majority of children with NHL of all subtypes are now cured. The similarities and differences between adult and childhood presentations of disease, and whether or not some subtypes of NHL and leukemia are the same or different disease entities, are interesting questions that will be addressed with advances in our understanding of the molecular and genetic bases of these diseases. As is the case with other pediatric malignancies, growing emphasis is now being placed on the development of less toxic, targeted therapeutic approaches, and this review highlights some of the biological discoveries that will potentially open these avenues.

High expression of Mcl-1 in ALK positive and negative anaplastic large cell lymphoma

AIM

To gain more insight into the genes involved in the aetiology and pathogenesis of anaplastic large cell lymphoma (ALCL).

METHODS

Serial analysis of gene expression (SAGE) was undertaken on the CD4+ALK+ (anaplastic lymphoma kinase positive) ALCL derived cell line Karpas299 and as comparison on CD4+ T cells. Quantitative reverse transcription polymerase chain reaction (RT-PCR) and immunohistochemistry were performed on five ALCL derived cell lines and 32 tissue samples to confirm the SAGE data.

RESULTS

High expression of Mcl-1 was seen in the Karpas299 cell line, whereas the two other antiapoptotic Bcl-2 family members, Bcl-2 and Bcl-X(L), were not detected in the SAGE library. Quantitative RT-PCR confirmed the high expression of Mcl-1 mRNA and low expression of Bcl-2 and Bcl-X(L) in Karpas299 and in four other ALCL cell lines. To expand on these initial observations, primary tissue samples were analysed for Mcl-1, Bcl-X(L), and Bcl-2 by immunohistochemistry. All 23 ALK+ and nine ALK- ALCL cases were positive for Mcl-1. Bcl-2 and Bcl-X(L) were expressed infrequently in ALK+ ALCL cases, but were present in a higher proportion of ALK- ALCL cases.

CONCLUSION

The consistent high expression of Mcl-1 in ALK+ and ALK- ALCL suggests that Mcl-1 is the main antiapoptotic protein in this disease. The high frequency of Mcl-1, Bcl-2, and Bcl-X(L) positive ALCL cases in the ALK- group compared with the ALK+ group indicates that ALK induced STAT3 activation is not the main regulatory pathway in ALCL.

Three children with CD30 cutaneous anaplastic large cell lymphomas bearing the t(2;5)(p23;q35) translocation

Since its discovery in CD30(+) anaplastic large cell lymphomas, the t(2;5)(p23;q35) translocation has shown a high degree of association with nodal disease, younger patient age, and better prognosis. Furthermore, primary cutaneous CD30(+) anaplastic large cell lymphomas rarely manifests the t(2;5) translocation. We present three cases of this disease that occurred in children, bore the t(2;5) translocation, and had excellent outcomes, but presented cutaneously. Two of these lesions were primary skin lymphomas. Review of the available literature in conjunction with these three cases suggests that the t(2;5) translocation may be more strongly associated with younger patient age and favorable outcomes rather than nodal versus cutaneous site of presentation.

Papel de la genética molecular en el cáncer infantil

In the last few years molecular genetic studies of childhood cancer have acquired great importance. Advances in these techniques have increased knowledge of the various genes involved in tumoral development. Genetic alterations can occur in three large groups of genes: oncogenes, tumor suppressor genes, and DNA repair genes. Cytogenetic analyses (karyotyping) are complemented by various molecular techniques, such as fluorescence in situ hybridization (FISH), reverse transcriptase-polymerase chain reaction (RT-PCR) and spectral karyotyping (SKY). These are the most reliable techniques and improve the sensitivity of karyotyping. The present article reviews the most representative and best characterized genes involved in the molecular etiology of childhood cancer, both hematologic malignancies (leukemia and lymphoma) and solid tumors (brain tumors, neuroblastoma, Wilms' tumor, hepatoblastoma, rhabdomyosarcoma, Ewing's sarcoma and retinoblastoma). Molecular techniques have enabled more precise diagnosis as well as identification of new prognostic factors and the development of more effective treatments. These techniques can also be useful in identifying minimal residual disease during and after treatment for leukemias, neuroblastomas and sarcomas, with the aim of predicting recurrence.

Anaplastic lymphoma kinase proteins and malignancy

The anaplastic lymphoma kinase (ALK) gene fuses to the nucleophosmin (NPM) gene as a result of a (2;5) translocation associated with a subtype of human lymphoma (initially designated anaplastic large cell lymphoma [ALCL] or Ki-1/CD30-positive lymphoma). The immunocytochemical detection of NPM-ALK (and proteins encoded by other ALK fusion genes) has allowed the definition of a tumor entity, "ALK-positive lymphoma" (which shows only partial overlap with pathologists' diagnosis of ALCL), to be defined and is invaluable in distinguishing this disease from ALK-negative large cell lymphomas. Eight variant ALK fusion proteins have been identified. Some are expressed only in ALCL, some are found only in the nonhematopoietic neoplasm inflammatory myofibroblastic tumor (IMT), and some are present in both types of malignancy. The ALK gene is silent in adult tissues except for restricted sites within the nervous system (consequently, patients with ALK-positive lymphoma produce antibodies to the ALK protein) but is expressed in some neuroblastomas and rhabdomyosarcomas. Biochemical studies suggest an anti-apoptotic function of NPM-ALK, and this may contribute to oncogenesis. Although ALK-positive lymphomas have a generally good prognosis, new therapeutic regimens are still needed for patients whose disease is refractory to conventional treatment.