title: Tumor microenvironment in mycosis fungoides and Sézary syndrome.
abstract: OBJECTIVE
  Mycosis fungoides and Sézary syndrome arise from malignant T cells that reside in skin, and subsequently are capable of circulating between skin, lymph nodes, and blood. The pathophysiologic mechanisms that cause and result in different behaviors of the skin-homing-malignant T cells in different stages of cutaneous T-cell lymphoma (CTCL) are still unknown. It is hypothesized that the skin microenvironment which is composed by various immune cell subsets as well as their spatial distribution and T-cell interaction through different chemokines and cytokines have an important role in the development and pathogenesis of CTCL and will be addressed in this chapter.
  
  
  RESULTS
  Recent studies have discovered that malignant T cells in Sézary syndrome are of the central memory T-cell subset, whereas those in mycosis fungoides are nonrecirculating skin-resident effector memory T cells, and have shown a protumorigenic role of mast cells and macrophages in CTCL. In addition, it has been observed that malignant T cells may exhibit features of one of these three distinct phenotypes (forkhead box P3 + regulatory T-cell phenotype, Th2 phenotype, and Th17 phenotype) and are functionally exhausted through an increased expression of certain coinhibitory molecules, such as programmed death-1.
  
  
  CONCLUSIONS
  All these new findings could assist in the development of novel targeted therapies for CTCL.
authors.affiliation: aDepartment of Pathology bDepartment of Hematology/Hematopoietic Cell Transplantation cDepartment of Surgery, Division of Dermatology, City of Hope, Duarte, California, USA.
authors.forename: Belen
authors.initials: B
authors.lastname: Rubio Gonzalez
authors.forename: Jasmine
authors.initials: J
authors.lastname: Zain
authors.forename: Steven T
authors.initials: ST
authors.lastname: Rosen
authors.forename: Christiane
authors.initials: C
authors.lastname: Querfeld
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology; D016207:Cytokines / Q000378:metabolism; D006801:Humans; D016410:Lymphoma, T-Cell, Cutaneous / Q000188:drug therapy / Q000378:metabolism / Q000473:pathology; D058990:Molecular Targeted Therapy / Q000379:methods; D009182:Mycosis Fungoides / Q000378:metabolism / Q000473:pathology*; D012751:Sezary Syndrome / Q000378:metabolism / Q000473:pathology*; D012878:Skin Neoplasms / Q000188:drug therapy / Q000378:metabolism / Q000473:pathology*; D013601:T-Lymphocytes / Q000473:pathology; D059016:Tumor Microenvironment
chemical_list: D000970:Antineoplastic Agents; D016207:Cytokines