Regulatory cells and human cancer

While there is now little debate about the existence or relevance of regulatory Populations of T cells to a variety of human diseases, including cancer, there is considerable debate about the ontogeny, phenotype, and mechanisms of action of given regulatory T cell Populations. This review will limit itself to discussion to two distinct populations of CD4+ regulatory T cells: T cells co-expressing the CD25 receptor (Tregs), and type 1 regulatory (TrI) T cells. Attention will be focused on the definition and role of these regulatory T cell populations in human cancers. (c) 2005 Elsevier Ltd. All rights reserved.