ALK kinase domain mutations in primary anaplastic large cell lymphoma: consequences on NPM-ALK activity and sensitivity to tyrosine kinase inhibitors

Diagnostic, Prognostic, and Predictive Role of Next-Generation Sequencing in Mature Lymphoid Neoplasms

Lymphoma is a clinically and biologically heterogeneous disease. Next-generation sequencing (NGS) has expanded our understanding of this heterogeneity at the genetic level, refining disease classification, defining new entities, and providing additional information that can be used in diagnosis and management. This review highlights some of the NGS findings in lymphoma and how they can be used as genetic biomarkers to aid diagnosis and prognosis and guide therapy.

Activation of IGF-1R pathway and NPM-ALK G1269A mutation confer resistance to crizotinib treatment in NPM-ALK positive lymphoma

ALK-positive anaplastic large cell lymphoma (ALCL) represents a subset of non-Hodgkin's lymphoma that is treated with crizotinib, a dual ALK/MET inhibitor. Despite the remarkable initial response, ALCLs eventually develop resistance to crizotinib. ALK inhibitor resistance in tumors is a complex and heterogeneous process with multiple underlying mechanisms, including ALK gene amplification, ALK kinase domain mutation, and the activation of various bypass signaling pathways. To overcome resistance, multiple promising next-generation ALK kinase inhibitors and rational combinatorial strategies are being developed. To determine how cancers acquire resistance to ALK inhibitors, we established a model of acquired crizotinib resistance by exposing a highly sensitive NPM-ALK-positive ALCL cell line to increasing doses of crizotinib until resistance emerged. We found that the NPM-ALK mutation was selected under intermediate-concentration drug stress in resistant clones, accompanied by activation of the IGF-1R pathway. In the crizotinib-resistant ALCL cell model, the IGF-1R pathway was activated, and combined ALK/IGF-1R inhibition improved therapeutic efficacy. Furthermore, we also detected the NPM-ALK G1269A mutation, which had previously been demonstrated to result in decreased affinity for crizotinib, in the resistant cell model. Although crizotinib was ineffective against cells harboring the NPM-ALK G1269A mutation, five structurally different ALK inhibitors, alectinib, ceritinib, TAE684, ASP3026 and AP26113, maintained activity against the resistant cells. Thus, we have shown that second-generation ALK tyrosine kinase inhibitors or IGF-1R inhibitors are effective in treating crizotinib-resistant tumors.

Enigmas in tumor resistance to kinase inhibitors and calculation of the drug resistance index for cancer (DRIC)

Darwinian selection is also applicable when antibiotics, the immune system or other host factors shape the repertoire of microorganisms, and similarly, clonal selection is the hallmark of tumor evolution. The ongoing revolution in new anti-cancer treatment modalities, combined with an unprecedented precision in characterizing malignant clones at the level below one percent, profoundly improves the understanding of repertoire-tuning mechanisms. There is no fundamental difference between selection of the tumor cells in the presence, or absence, of therapy. However, under treatment the influence of a single agent can be measured, simplifying the analysis. Because of their beneficial and selective therapeutic effect, the focus in this review is set on protein kinase inhibitors (PKIs), predominantly tyrosine kinase inhibitors (TKIs). This is one of the most rapidly growing families of novel cancer medicines. In order to limit the number of drugs, the following representative target kinases are included: ALK, BCR-ABL, BRAF, BTK, and EGFR. A key therapeutic challenge is how to reduce tumor growth after treatment, since this is rate-limiting for the generation and expansion of more malignant escape mutants. Thus, upon efficient treatment, tumor cell loss often enables a profoundly increased growth rate among resistant cells. Strategies to reduce this risk, such as concomitant, competitive outgrowth of non-transformed cells, are described. Seven parameters: 1. Drug type, 2. tumor type, 3. presence of metastases or phenotypic change, 4. tumor cell number, 5. net growth rate (proliferation minus cell death), 6. inherited genetic- and 7. epigenetic- variations are crucial for drug responses. It is envisaged that it might become possible to calculate a clinically relevant Drug Resistance Index for Cancer (DRIC) for each patient.

ALK-positive anaplastic large cell lymphoma with soft tissue involvement in a young woman

INTRODUCTION

Anaplastic large cell lymphoma (ALCL) is a type of non-Hodgkin lymphoma that has strong expression of CD30. ALCL can sometimes involve the bone marrow, and in advanced stages, it can produce destructive extranodal lesions. But anaplastic large cell lymphoma kinase (ALK)+ ALCL with soft tissue involvement is very rare.

CASE REPORT

A 35-year-old woman presented with waist pain for over 1 month. The biopsy of soft tissue lesions showed that these cells were positive for ALK-1, CD30, TIA-1, GranzymeB, CD4, CD8, and Ki67 (90%+) and negative for CD3, CD5, CD20, CD10, cytokeratin (CK), TdT, HMB-45, epithelial membrane antigen (EMA), and pan-CK, which identified ALCL. After six cycles of Hyper-CVAD/MA regimen, she achieved partial remission. Three months later, she died due to disease progression.

CONCLUSION

This case illustrates the unusual presentation of ALCL in soft tissue with a bad response to chemotherapy. Because of the tendency for rapid progression, ALCL in young adults with extra-nodal lesions are often treated with high-grade chemotherapy, such as Hyper-CVAD/MA.

ALK-positive anaplastic large cell lymphoma with prominent bone involvement in a 13-year-old boy

Introduction

Anaplastic lymphoma kinase-positive (ALK+) anaplastic large cell lymphoma (ALCL) is a type of non-Hodgkin lymphoma, which has strong expression of cluster of differentiation (CD)-30 and ALK. ALCL sometimes can involve the bone marrow, and in advanced stages, it can produce destructive bone lesions. But ALK+ ALCL with prominent bone involvement is very rare, especially in children.

Case report

A 13-year-old boy presented with waist pain and low-grade fever for 8 months. The biopsy of soft tissue lesions around the thoracic spine showed that these cells were positive for ALK-1, CD30, leukocyte common antigen, CD3, CD4, and CD8, as well as being negative for epithelial membrane antigen and pan-cytokeratin, which revealed ALCL. After six cycles of a regimen consisting of hyperfractionated cyclophosphamide, vincristine, doxorubicin, and dexamethasone/methotrexate and cytarabine (hyper-CVAD/MA) and autologous hematopoietic stem cell transplantation, he achieved complete remission (CR).

Conclusion

It is generally believed that the regimen consisting of cyclophosphamide, hydroxydaunorubicin (doxorubicin), vincristine, and prednisolone (CHOP) is also applicable to ALCL. Because of the tendency of rapid progression and the frequency of B symptoms, ALCL in children and young adults is treated with high-grade chemotherapy such as hyper-CVAD/MA.