We are interested in identifying cancer stem cell markers in malignant melanoma. Cancer stem cells are defined as the tumor initiation cells in cancer progression and have been postulated to be the chemoresistant population after systemic treatment of cancer. Understanding the biological properties of these cells will facilitate greatly the process of cancer control. Metastasis is a process whereby cancer cells migrate to a distant organ and proliferate there to form a tumor mass, therefore metastatic cancer cells are assumed cancer stem cells. A population of cells that produce more metastases thus must contain more cancer stem cells than a population of cells that produce fewer metastases. Based on this rationale, we propose to identify more cancer stem cell markers in malignant melanoma, which is highly resistant to current therapies, using cell lines with increased metastatic abilities. We previously generated melanoma cell lines with increased metastatic abilities using an experimental metastasis model. Using DNA microarray analyses, we compared the gene expression profiles between the samples from the derived cells and those from the parental line and identified the differentially expressed genes. These genes were found to correlate with the aggressiveness of human melanoma metastases and a poor survival in melanoma metastases-carrying patients, suggesting strongly their relevance to human melanoma progression. We hypothesize that they might be melanoma stem cell markers and will test this in xenograft animal models.
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