Thursday 25 February 2010
Video : Comparison of primary and metastatic acral melanoma by whole genome sequencing.
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When compared to the most frequent melanoma type (superficial spreading melanoma or SSM), melanomas on acral skin invariably showed gene amplifications.
The amplified regions in acral melanomas frequently contain known oncogenes such as HRAS, cyclin D1, CDK4, HTERT, but also involve regions without obvious candidate genes.
Amplifications were defined as focused chromosomal regions with marked copy number increase (>2.5-fold of ploidy).
Whereas all acral melanomas appeared to have at least one amplification, most had several, less than 15% of nonacral melanomas had amplifications.
Additional studies showed that the amplifications in acral melanomas arise very early in the progression, at or even before the in situ stage of the disease (see the section on field cells below).
In contrast, the few nonacral melanomas that do display amplifications appear to have acquired them later during progression.
Bastian BC, Kashani-Sabet M, Hamm H et al. Gene amplifications characterize acral melanoma and permit the detection of occult tumor cells in the surrounding skin. Cancer Res. 2000; 60; 1968–1973.