An Exploration into the Origins and Pathogenesis of Anaplastic Large Cell Lymphoma, Anaplastic Lymphoma Kinase (ALK)-Positive

Role of ALK Inhibitors in Anaplastic Large Cell Lymphoma-Experience from an Indian Center

Perumal Kalaiyarasi JayachandranAnaplastic large cell lymphoma (ALCL) is the second most common type of peripheral T cell lymphoma and an aggressive mature T cell lymphoma. About 50 to 70% of systemic ALCLs are anaplastic lymphoma kinase positive (ALK +), the proportion even higher in the pediatric population. The 5-year survival after chemotherapy is around 70 to 80%. But there is a subgroup of ALK+ ALCL patients who are refractory to chemotherapy. Brentuximab vedotin is an approved agent for such patients. The activity of ALK inhibitors in ALK+ non-small cell lung cancer is well known and has been approved for use. The efficacy and safety of ALK inhibitors in ALK + ALCL are largely under-reported. Here we have reported our experience in the use of ALK inhibitors in relapsed refractory ALK+ ALCL.

Cell of Origin and Immunologic Events in the Pathogenesis of Breast Implant-Associated Anaplastic Large-Cell Lymphoma

Breast implant–associated anaplastic large-cell lymphoma (BIA-ALCL) is a CD30-positive, anaplastic lymphoma kinase–negative T-cell lymphoma. Nearly all cases have been associated with textured implants. Most cases are of effusion-limited, indolent disease, with an excellent prognosis after implant and capsule removal. However, capsular invasion and tumor mass have a more aggressive course and a fatal outcome risk. This review summarizes the current knowledge on BIA-ALCL cell of origin and immunologic factors underlying its pathogenesis. Cytokine expression profiling of BIA-ALCL cell lines and clinical specimens reveals a predominantly type 17 helper T-cell (Th17)/Th1 signature, implicating this as its cell of origin. However, a Th2 allergic inflammatory response is suggested by the presence of IL-13, with infiltration of eosinophils and IgE-coated mast cells in clinical specimens of BIA-ALCL. The microenvironment-induced T-cell plasticity, a factor increasingly appreciated, may partially explain these divergent results. Mutations resulting in constitutive Janus kinase (JAK)–STAT activation have been detected and associated with BIA-ALCL pathogenesis in a small number of cases. One possible scenario is that an inflammatory microenvironment stimulates an immune response, followed by polyclonal expansion of Th17/Th1 cell subsets with release of inflammatory cytokines and chemokines and accumulation of seroma. JAK-STAT3 gain-of-function mutations within this pathway and others may subsequently lead to monoclonal T-cell proliferation and clinical BIA-ALCL. Current research suggests that therapies targeting JAK proteins warrant investigation in BIA-ALCL.