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Background: Gap junctions are intercellular channels composed of connexins, which mediate the direct passage of small molecules between neighbouring cells. They are involved in regulation of cell cycle, cell signalling, and differentiation, and probably invasion and metastasis. The role of connexins in the metastatic process is controversial, because some studies indicate that connexin expression is inversely correlated with metastatic capacity. In contrast, others demonstrate that connexins may be involved in metastasis. In addition, connexin status in breast cancer metastasis has not been widely studied. Methods: We evaluated by immunohistochemistry the expression of connexin 26 (Cx26) and connexin 43 (Cx43) in primary breast tumours (PTs) and matched paired metastases to lymph nodes (MLNs). Results: In PTs, we observed predominantly cytoplasmic localisation of evaluated connexins, indicating alterations in connexin expression in breast cancer cells. We demonstrated that expression of Cx26 and Cx43 was increased in MLNs compared with PTs (p < 0.00001 and p < 0.001, for CX26 and Cx43, respectively). In addition, Cx26 and Cx43 negative PTs developed Cx26 and Cx43 positive MLNs. Furthermore, besides increased cytoplasmic staining, enhanced membranous localisation of Cx43, typical of normal cells, was found in MLNs. Additionally, membranous Cx26 expression appeared only in metastatic breast cancer cells. Conclusions: These findings suggest that connexins may contribute to the efficient metastasising of breast cancer to the lymph nodes. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate Bcl-2 expression in the germinal centers of adenoid in children on the assumption that it can be treated as a marker of adenoidal tissue function. The study involved 95 children. The patients were divided into three age groups: aged up to 5, 5–10 and above 10 years. The analysed material were adenoids removed on the grounds of hypertrophy. Immunohistochemical analyses were carried out using monoclonal antibodies (DAKO/Bcl-2, No. M0887) directed against human Bcl-2 protein. The presence of Bcl-2 positive lymphocytes within the lymphoid follicles and Bcl-2 immunostaining were scored. The immunohistochemical staining showed Bcl-2 positive lymphocytes in the examined sections of adenoidal tissue and their characteristic location, mainly within the mantle zone. Bcl-2 reactivity was widespread in hyperplastic lymphoid tissue, including germinal centers surroundings, scattered cells within the germinal centers and the T-cell areas in general. We have not found statistically significant correlation between Bcl-2 expression and clinical status and change in Bcl-2 expression level according to age. The apoptosis presence within the germinal centers and its lack in mantle zone, the manifestation of which is Bcl-2 expression, is a sign of a proper lymphocytes maturation within lymphoid follicles. It seems that these processes are not influenced by age, so the adenoid involution is probably associated with the changes in the number of lymphoid follicles rather than change or inhibition of the processes that take place in them. [Copyright &y& Elsevier]