Reelin and its receptors, VLDLR and ApoER2, in melanocytic nevi.

Reelin is an extracellular signaling protein synthesized by Cajal-Retius cells in utero and early after birth, its presence being signaled in adult life too. Reelin acts on its receptors, VLDLR and ApoER2, acting on cytoskeleton, controlling migration and subsequently positioning and stabilizing the cortical neurons. We investigated the reelin presence and its receptors, VLDLR and ApoER2, in melanocytic nevi considering the neural crest origin of the nevus cells and their migration into skin during embrionary period. Melanocytic nevi present a strict cellular architecture and an increased malignant transforming capacity. We investigated reelin presence in 32 melanocytic nevi (5 junctional, 27 compound or 14 dysplastic nevi and 18 non dysplastic nevi). The assessment of reelin presence was performed by histological semiquantitative criteria. Results showed the presence of reelin in 29 cases (29/ 32). The presence of reelin was elevated in junctional areas as in dysplastic nevi. VLDLR presented positive values in 16 cases (16/ 32) and ApoER2 was weak positive in 7 cases. Reelin or its receptors was peritumorally absent. Our study showed the presence of reelin in nevus cells from cutaneous melanocytic nevi and, in these cells, only the VLDLR receptor was present in half of the cases. The significance of the reelin presence in cutaneous nevus cells may be hypothetically considered correlated with the position maintenance of the nevus cells or migration of these cells in malignant transforming situation. Abbreviations: ApoER2 = apolipoprotein receptor 2, VLDLR = very low density lipoprotein receptor, DAB-1 = DIABLO protein, HMB45 = gene HMB45.