The biological environment of Hodgkin's lymphoma and the role of the chemokine CCL17/TARC.

Hodgkin's lymphoma is a lymphoproliferative disease, which differs in its morphology and therapeutic response from other lymphomas. Neoplastic cells represent only a minor cell population of the tumour, while the major part of the tumour is formed by inflammatory cells. It results from the production of cytokines and chemokines both by neoplastic cells and by inflammatory cells. An important prognostic marker in Hodgkin's lymphoma appears to be the chemokine (C-C motif) ligand 17 (CCL17), also known as thymus and activation-related chemokine (TARC). This chemokine is expressed by many cell types and tissues, and in the case of Hodgkin lymphoma, also by Reed-Sternberg cells. CCL17/TARC binds to chemokine receptors CCR4 and CCR8 and displays chemotactic activity for T lymphocytes and some other leukocytes. The understanding of biological pathways in Hodgkin's lymphoma could be important for monitoring of disease activity and for the development of future targeted therapy.