EXPRESSION OF SELECTIN LIGANDS BY CUTANEOUS SQUAMOUS-CELL CARCINOMA

Recent evidence suggests that interactions between endothelial selecti ons and tumor surface selectin ligands may be of importance in cancer metastasis. To investigate the role of such mechanisms in cutaneous tu mors, whole skin biopsies were examined immunohistochemically for a va riety of selectin ligands including sialyl-Lewis-X, sialyl-Lewis-A (S- Lea), sulfatides, and CD15. In 12 of 12 squamous cell carcinomas (SCCs ), there was expression of sialyl-Lewis-X and CD15, but no tumor expre ssed S-Lea. Occasional keratinocytes in eight of 12 SCCs expressed sul fatides. All selectin ligands were absent on keratinocytes in basal ce ll carcinomas (BCCs, n = 8) and normal skin (n = 8), with the exceptio n of one BCC that expressed S-Lea E-selectin was not present in normal skin, but was strongly expressed by dermal endothelium in both SCC an d BCC Keratinocyte cell lines A431, HaCaT, and SVK14 were investigated by flow cytometry, which demonstrated sialyl-Lewis-X and S-Lea expres sion by all three, whereas normal human keratinocytes did not express these molecules. These findings suggest a potential role for selectin- mediated events in early and late metastasis, and differential express ion of these ligands by BCC and SCC may explain the relatively low met astatic potential of the former.