We identified 254 genes whose expression was associated with metastatic dissemination of cutaneous melanomas. These genes may shed light on the molecular mechanisms underlying poor prognosis in melanoma patients.

Metastatic disease is the primary cause of death in cutaneous malignant melanoma (CMM) patients. To understand the mechanisms of CMM metastasis and identify potential predictive markers, we analyzed gene-expression profiles of 34 vertical growth phase melanoma cases using cDNA microarrays. All patients had a minimum follow-up of 36 months. Twenty-one cases developed nodal metastatic disease and 13 did not. Comparison of gene expression profiling of metastatic and nonmetastatic melanoma cases identified 243 genes with a >2-fold differential expression ratio and a false discovery rate of <0.2 (206 up-regulated and 37 down-regulated). This set of genes included molecules involved in cell cycle and apoptosis regulation, epithelial-mesenchymal transition (EMT), signal transduction, nucleic acid binding and transcription, protein synthesis and degradation, metabolism, and a specific group of melanoma-and neural-related proteins. Validation of these expression data in an independent series of melanomas using tissue microarrays confirmed that the expression of a set of proteins included in the EMT group (N-cadherin, osteopontin, and SPARC/osteonectin) were significantly associated with metastasis development. Our results suggest that EMT-related genes contribute to the promotion of the metastatic phenotype in primary CMM by supporting specific adhesive, invasive, and migratory properties. These data give a better understanding of the biology of this aggressive tumor and may provide new prognostic and patient stratification markers in addition to potential therapeutic targets. [Cancer Res 2007;67(7):3450-60]

Cutaneous malignant melanoma remains the leading cause of skin cancer death in industrialized countries. Clinical and histological variables that predict survival, such as Breslow's index, tumor size, ulceration, or vascular invasion have been identified in malignant melanoma. Nevertheless, the potential relevance of biological variables still awaits an in-depth exploration. Using tissue microarrays (TMAs), we retrospectively analyzed 165 malignant melanoma samples from 88 patients corresponding to distinct histological progression phases, radial, vertical, and metastases. A panel of 39 different antibodies for cell cycle, apoptosis, melanoma antigens, transcription factors, DNA mismatch repair, and other proteins was used. Integrating the information, the study has identified expression profiles distinguishing specific melanoma progression stages. Most of the detected alterations were linked to the control of cell cycle G1/S transition; cyclin D1 was expressed in radial cases 48% (12 of 25) with significant lost of expression in vertical cases 14% (9 of 65), P = 0.002; whereas p16(INK4a) (89% in vertical versus 71% in metastatic cases, P = 0.009) and p27(KIP1) (76% in radial versus 45% in vertical cases, P = 0.010) were diminished in advanced stages. The study also defines a combination of biological markers associated with shorter overall survival in patients with vertical growth phase melanoma, that provided a predictor model with four antibodies (Ki67, p16(INK4a), p21(CIP1), and Bcl-6). This predictor model was validated using an independent series of 72 vertical growth phase melanoma patients.