Because previous research indicated that tetraspanins may contribute to the metastatic process (Boucheix et al, 2001; Hemler, 2005; Zöller, 2009), we next analysed the cell surface expression profiles of other tetraspanins (CD9, CD53, CD63, CD81, CD82 and CD151) on invasive and non-invasive melanoma cells. The gene discussed is CD9; the disease is melanoma.