Functional implications of HNK-1 expression on invasive behaviour of melanoma cells.

HNK-1 epitope, also known as CD57, is expressed on a wide range of cells and has been related to cell to cell and cell to extracellular matrix interactions. Expression of the HNK-1 epitope has been considered a prognostic factor in several tumours, as it has been associated with the risk of metastasis. HNK-1 has been found to be expressed on uveal and cutaneous melanoma and proposed as a useful marker of the risk of metastasis. We have analysed the HNK-1 expression on a large panel of melanoma cell lines, the involvement of this epitope in melanoma cell adhesion, as well as its migrative and invasive behaviour. HNK-1 was highly expressed in 12.9% of melanoma cell lines, and in vitro experiments using invasive melanoma cell lines demonstrated that an HNK-1 blockade reduces cell adhesion to extracellular matrix as well as their migrative and invasive ability. These data support the functional relevance of HNK-1 expression in metastatic melanoma.