A key event in cancer metastasis is the migration of tumour cells from their original location to a secondary site. The development of melanoma may be viewed as a consequence of the disruption of homeostatic mechanisms in the skin of the original site. To investigate whether dysregulation of cell motility (Cdc42 expression), escaping the control of cell-cell and cell-matrix interactions (E-cadherin, beta-catenin expression), enhances melanoma progression, and whether chemokine receptors (CXCR4) mediate cell migration and activation during invasion and metastasis development. The immunohistochemical expression of Cdc42, E-cadherin, beta-catenin and CXCR4 was investigated in 30 patients with surgically treated nodular melanoma, 18 alive and disease free and 12 with a fatal outcome due to metastatic disease. E-cadherin expression was significantly reduced (P < 0.05) and cytoplasmic beta-catenin was increased in the patients who had died compared with disease-free individuals, while membrane expression of beta-catenin was similar in the two groups. Patients with fatal outcome had increased Cdc42 (P < 0.01) and CXCR4 (P < 0.05). In this group a positive correlation was found between melanocytic Cdc42 expression and Breslow thickness (r = 0.598, P < 0.05) and between CXCR4 expression and Breslow thickness (r = 0.583, P < 0.05). Findings suggest that primary cutaneous melanoma with a high Breslow thickness is characterized by tumour cells with high motility and invasion ability, in line with the hypothesis that low E-cadherin levels and overexpression of Cdc42 and CXCR4 could be prognostic markers of poor outcome.