Cutaneous melanoma is the most serious form of skin cancer and one of the most common cancers in young adults. Its incidence is increasing at a significant rate, and the long-term survival rate for patients with melanoma has not improved markedly since the 1970s. Our laboratory identified unexpected subtypes of human cutaneous melanoma and observed a unique pattern of gene expression in highly invasive melanomas1. However, the study design for this initial report did not allow a direct correlation of gene expression profiles with disease progression or response to therapy. We have begun to address the relationship between gene expression profile and clinical outcome by collecting and analyzing a set of melanoma tumor biopsy samples with known clinical outcome. We have supplemented this set of samples with a melanoma tissue microarray. The examination of gene expression patterns of melanoma tumors will provide a unique opportunity to study a homogeneous group of patients and determine whether gene expression patterns can assist in predicting disease progression or therapeutic response.