Melanomas grow in two phases: radial and vertical. Vertical-phase tumors are more likely to metastasize (spread cancer to other parts of the body) than radial melanomas.
Christopher Haqq and colleagues dissected a large primary melanoma into radial and vertical portions, and through microarray techniques found that, in the transition from radial to vertical growth, the melanomas lost the expression of certain molecules, resulting in increased risk of metastasis.
However, some metastatic tumors retained a gene expression pattern characteristic of the radial growth phase, which implies that both radial and vertical melanomas can metastasize. The authors identified over 2,000 genes that distinguished the stages of melanoma progression.
The authors say that their results will provide a basis for developing new molecular diagnostic techniques and, eventually, targeted therapies for patients with skin cancer.
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