Bittner et al. (2001), in a study involving 11 different institutions, brought modern molecular techniques to this important type of cancer, whose incidence is rising steeply. Melanomas have no histopathologic, molecular, or immunochemical markers to differentiate subsets of patients. There are few known recurring genetic or cytogenetic changes in these tumors, and non-surgical treatment is notoriously ineffective in cases of advanced disease. With a clever visual clustering of gene expression data for 31 patients, 19 were concentrated in the major cluster, whereas the rest were distributed rather widely. Just 22 genes accounted for much of the separation between the major cluster and the other specimens; 19 have known functions.
A substudy examined cell lines from very invasive malignant melanomas of the uvula, together with the cutaneous melanomas. The molecular assays were combined with bioassays. First, a simulated scratch wound was made in plated cells, to see whether the cells would grow out, how far they would migrate, and how rapidly they moved away from the initial site. The cells from the invasive lesions migrated dramatically from the initial position. Second, these cells actively stimulated coagulation of collagen in the gel. And, finally, the most invasive melanoma cells pushed a trabecular framework aside. In these bioassays, the 31 cutaneous melanoma specimens showed remarkable differentiation: The major cluster of 19 melanomas had downregulation of several genes related to spreading, migration, and formation of focal adhesions (integrins, syndecan 4, vin-culin), whereas the mixed group of 12 other melanomas had an opposite pattern, with higher activities associated with invasiveness, notably fibronectin, a promigratory molecule. Preliminary survival data (7/10 vs. 1/5 for major vs. nonmajor clusters) showed differences. Clearly, longer follow-up and confirmatory studies are needed.
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Complete Guide to Preventing Skin Cancer. We all know enough to fear the name, just as we do the words tumor and malignant. But apart from that, most of us know very little at all about cancer, especially skin cancer in itself. If I were to ask you to tell me about skin cancer right now, what would you say? Apart from the fact that its a cancer on the skin, that is.