The Germinal centre-derived lymphomas seen through their cellular microenvironment

The human lymph node is a complex tissue resulting from the microenvironmental organisation of different cell populations linked by topographical and/or functional relationships. Germinal centres (GCs) of lymphoid follicles contain a meshwork of follicular dendritic cells in addition to B-cells and some CD4⁺ T cells. Moreover, there is a sharp demarcation around the whole follicle centre, which is highlighted by fibroblastic reticulum cells. On the whole, GC exerts a role in B cell physiology and malignancy. In GC-derived lymphomas, gene expression profiling studies have raised the possibility that survival of the affected patients may be associated with signatures preferentially expressed in non-malignant T cells and macrophages and/or dendritic cells. Immunohistological analyses in lymphoma biopsy samples have confirmed that the biological behaviour and tumour progression may be influenced by the tumour microenvironment. This review will examine GC-derived lymphomas, including follicular lymphomas, Hodgkin lymphomas and angioimmunoblastic T-cell lymphoma, through their integrated cellular microenvironment, highlighting those findings which may serve as a useful surrogate marker for tumour diagnosis or tumour progression, together with key molecules involved in tumour development.