Comparison of integrin adhesion molecules expressed by primary brain lymphomas and nodal lymphomas

The expression of 17 adhesion molecules was immunohistochemically examined in 5 primary cerebral lymphomas (PCL) and in 5 histologically similar nodal lymphomas (NL) to evaluate their possible involvement in selective targeting of lymphoma cells to the brain. PCL and NL tumor cells showed very similar expression patterns: they were consistently positive for ₃, ₄ and ₁ integrin chains; negative for ₂, ₆, ₃ and ₄ integrin chains; and heterogeneous for ₅, _L, _M, _X, ₂ and ₇ integrin chains, as well as for intercellular adhesion molecule-1 (ICAM-1) and the selectin LECAM-1. Loosely infiltrating PCL showed lower levels of the _L2 integrin than compact cell clusters. Vessels stained for ICAM-1 and vascular cell adhesion molecule-1 (VCAM-1). We conclude that the adhesion molecules implicated in the extravasation of non-neoplastic leukocytes (₄₁/VCAM-1 and _L2/ICAM-1) are also expressed by both PCL and NL. The adhesion molecules examined are apparently not selective mediators of lymphoma cell homing to the brain, but at least _L2 integrin might be related to the infiltration pattern of PCL within the brain parenchyma.Supported by the Sander Foundation