ATP-binding cassette transporter ABCB5 gene is expressed with variability in malignant melanoma.

BACKGROUND Melanoma is a malignant neoplasm with high metastatic disease risk and elevated mortality. Incidence of melanoma varies according to geographic region and genetic BACKGROUND Epidemiological studies indicate that acral melanoma (AM) is among the most common melanomas in the Mexican population. While extensive studies have identified genes associated with melanoma, little is known about the genes involved in the pathogenesis of AM. OBJECTIVE To compare the gene expression patterns between primary melanoma and normal skin. METHODS We used 10 samples of fresh acral melanomas and normal skin for the study of differential gene expression and 22 samples of melanoma for in situ hybridization. RESULTS We first identified a gene that was present in a sample of AM and absent in normal skin. DNA sequencing of this differentially expressed gene revealed that it corresponded to ABCB5, a gene recently implicated in the regulation of progenitor cell fusion. Furthermore, we detected ABCB5 expression in other melanoma specimens by RT-PCR. We showed that nine out of ten melanomas were positive for ABCB5 while only one melanoma and normal skin samples were negative. All ABCB5 expressing melanomas had variable gene expression according to in situ hybridization studies, suggesting that the ABCB5 gene may be differentially regulated by individual melanomas. CONCLUSIONS The ABCB5 gene may be related to the properties of chemoresistance and aggressiveness of melanoma. The high expression found in samples of acral melanoma may provide more insight on the pathogenesis of this common type of melanoma in the Mexican population, frequently associated with poor prognosis.