Altered expressions of HOX genes in human cutaneous malignant melanoma

HOX genes act as master genes to control morphogenesis. In human, HOX genes form 4 clusters composing 9 to 11 HOX genes (39 genes in total) on different chromosomes. We hypothesized that aberrant expression of HOX genes was associated with development and subsequent progression of melanoma and that the 39 HOX gene expression pattern determined the sites where melanoma grew. The expression levels of 39 HOX genes in 15 human cutaneous melanoma specimens and 7 nevus pigmentosus specimens were quantified by a comprehensive analysis system based on the real-time RT-PCR method. We found that the expression levels of HOXA11, A13, B9, D12 and D13 in melanoma were higher than those in nevus pigmentosus and that the expression levels of HOXA11, B2 and C13 were significantly different between pT4 melanoma and pT1 to pT3 melanoma. It was most notable that the expression levels of HOXA1, A2, C4 and B13 in melanoma with distant metastasis were higher than those in melanoma without it. On the other hand, we found no relationship between HOX genes expression patterns and the growing sites of melanoma. These results indicated that the misexpressions of some specific HOX genes were implicated in melanoma genesis and metastasis but had no linkage with melanoma sites.