Cadherins in reactive lymph nodes and lymphomas: high expression in anaplastic large cell lymphomas

Using a polyclonal pan-cadherin antibody and a monoclonal E-cadherin antibody (HECD-1) we have investigated cadherin expression in lymphomas and reactive lymph nodes. Routinely processed tissue from nine reactive lymph nodes and 48 lymphomas (six T-cell, six high-grade B-cell, 15 low-grade B-cell, 13 anaplastic large cell and eight Hodgkin's disease) were immunostained. The reactive cases showed pan-cadherin membrane associated staining of endothelium and epithelioid granulomas. No staining of lymphoid cells was seen. Pan-cadherin immunostaining was present in three of six T-cell lymphomas, two of six high-grade B-cell lymphomas, 12 of 13 anaplastic large cell lymphomas and three of eight cases of Hodgkin's disease. No staining of low-grade B-cell lymphomas was identified with the pan-cadherin antibody. E-cadherin was not detected in any of the lymphomas that showed pan-cadherin expression. The frequent and strongest cadherin expression in anaplastic large cell is noteworthy. The tumour cells of this lymphoma subtype are characterized by copious cytoplasma and a cohesive appearance, features which impart a superficial resemblance to carcinoma cells. Since cadherin molecules are known to have major morpho-regulatory functions our data suggests that the expression of cadherin molecules by anaplastic large cell lymphomas may play an important role in determining their characteristic epithelioid phenotype.