New insights in Diffuse Large B Cell Lymphoma Pathobiology

Diffuse large B cell lymphoma (DLBCL) is the most common non-Hodgkin lymphoma (NHL), accounting for about 40% of all cases NHL. Analysis of the tumour microenvironment is an important aspect of the assessment of the progression of DLBCL. In this review article, we have analyzed the role of different cellular components of the tumour microenvironment, including mast cells, macrophages, lymphocytes, in tumour progression of DLBCL. We examined several approaches to confront the available pieces of evidence; three key points emerged. DLBCL is a disease of malignant B-cells spreading and accumulating both at nodal and in extranodal sites. Both in patients with nodal and extranodal lesions, the subsequent induction of a cancer-friendly environment appears pivotal. DLBCL cell interaction with mature stromal cells and vessels confers tumour protection and inhibition of immune response while delivering nutrients and oxygen supply. Single cells may also reside and survive in protected niches in the nodal and extranodal sites as a source for residual disease and relapse. This review aims to molecularly and functionally recapitulate the DLBCL-milieu crosstalk, to relate niche and pathological angiogenic constitution and interaction factors to DLBCL progression.