Metallothionein immunoreactivity profile in B-cell lymphomas of the palatine tonsils

Abstract

Introduction. Tumours stimulate the remodelling of their microenvironment for their own survival. To protect their own growth and induce angiogenesis, tumours change the structure of the extracellular matrix and alter the function of existing as well as chemo-attracting immune system cells. MT is an anti-apoptotic and pro-proliferative protein that is also responsible for modulating the response of immune system cells. The expression of this protein by the fibroblasts of the tumour microenvironment is probably related to the remodelled phenotype of these cells by tumour influence on cancer-associated fibroblasts. Vimentin is a protein that appears to be the marker for the mesenchymal transition of cells from the epithelial phenotype. These cells seem to acquire the mesenchymal phenotype so that they can migrate and facilitate the development of metastases. Interestingly, the expression of vimentin has also been observed in the tumour microenvironment and may serve as a marker of a remodelled stroma in the process of facilitating tumour spread. Materials and methods. We recruited 25 patients with tonsillar DLBCL (diffuse large B-cell lymphoma) and tonsillar DLBCL with cervical lymph node involvement (i.e. stages I and II of the disease) and analysed tissue samples from the lymphoma and tumour microenvironment of each. We also analysed the immunoreactivity levels of the following antigens in the palatine tonsil lymphoma and its stroma: MT, vimentin, and CD56- and CD57-positive cells. Results. A statistically significantly higher MT and vimentin immunoreactivity was observed in the lymphoma as compared to the stroma tissue samples. However, both MT-positive fibroblasts and MT-positive macrophages were observed in the stroma. Additionally, statistically significantly lower numbers of CD56- and CD57-positive cells were identified in the lymphoma and the stroma samples than in the reference group samples. Conclusions. The high vimentin immunoreactivity in the tumour and its stroma, together with MT-expressing fibroblasts and macrophages, as well as a CD56- and CD57-positive cell deficit, would seem to confirm microenvironment remodelling and the participation of MT in tumour remodelling.