Melanoma progression, gene expression and DNA microarrays

In recent years DNA microarray analyses of gene expression changes in melanoma have been employed in an effort to better understand the processes of disease progression. Typically, the samples assessed are taken directly from tissue biopsies of distinct clinical stages. Apart from noting a significant shift in gene expression at the transition from thin to thick primary lesions, surprisingly little else has been learned. Furthermore, experiments performed using cell cultures derived from distinct clinical stages have entirely failed to identify a consistent stage-specific gene expression signature. This review compares the two approaches, discusses what was learned about the molecular nature of melanoma progression, and considers why stage-specific gene expression may be more complicated than originally thought.