Immune response to the ALK oncogenic tyrosine kinase in patients with anaplastic large-cell lymphoma

Treatment Options for Paediatric Anaplastic Large Cell Lymphoma (ALCL): Current Standard and beyond

Anaplastic Lymphoma Kinase (ALK)-positive Anaplastic Large Cell Lymphoma (ALCL), remains one of the most curable cancers in the paediatric setting; multi-agent chemotherapy cures approximately 65–90% of patients. Over the last two decades, major efforts have focused on improving the survival rate by intensification of combination chemotherapy regimens and employing stem cell transplantation for chemotherapy-resistant patients. More recently, several new and ‘renewed’ agents have offered the opportunity for a change in the paradigm for the management of both chemo-sensitive and chemo-resistant forms of ALCL. The development of ALK inhibitors following the identification of the EML4-ALK fusion gene in Non-Small Cell Lung Cancer (NSCLC) has opened new possibilities for ALK-positive ALCL. The uniform expression of CD30 on the cell surface of ALCL has given the opportunity for anti-CD30 antibody therapy. The re-evaluation of vinblastine, which has shown remarkable activity as a single agent even in the face of relapsed disease, has led to the consideration of a revised approach to frontline therapy. The advent of immune therapies such as checkpoint inhibition has provided another option for the treatment of ALCL. In fact, the number of potential new agents now presents a real challenge to the clinical community that must prioritise those thought to offer the most promise for the future. In this review, we will focus on the current status of paediatric ALCL therapy, explore how new and ‘renewed’ agents are re-shaping the therapeutic landscape for ALCL, and identify the strategies being employed in the next generation of clinical trials.

Translocations involving anaplastic lymphoma kinase (ALK)

Anaplastic large-cell lymphoma (ALCL) comprises a group of non-Hodgkin's lymphomas (NHLs) that were first described in 1985 by Stein and co-workers and are characterized by the expression of the CD30/Ki-1 antigen (Stein et al., 1985). Approximately half of these lymphomas are associated with a typical chromosomal translocation, t(2;5)(p23;q35). Much confusion about the exact classification and clinicopathological features of this subgroup of NHL was clarified with the identification of NPM-ALK (nucleophosmin-anaplastic lymphoma kinase) as the oncogene created by the t(2;5) (Morris et al., 1994). With the discovery of NPM-ALK as the specific lymphoma gene mutation, this NHL subtype could be redefined on the molecular level. This achievement was enhanced by the availability of specific antibodies that recognize ALK fusion proteins in paraffin-embedded lymphoma tissues. Several excellent recent reviews have summarized the histopathological and molecular findings of ALCL and their use in the classification of this lymphoma entity (Anagnostopoulos and Stein, 2000; Benharroch et al., 1998; Drexler et al., 2000; Foss et al., 2000; Gogusev and Nezelof, 1998; Kadin and Morris, 1998; Ladanyi, 1997; Morris et al., 2001; Shiota and Mori, 1996; Skinnider et al., 1999; Stein et al., 2000). This review will focus on the molecular function and signal transduction pathways activated by ALK fusion oncogenes, with recent advances and possible clinical implications to be discussed.