Abstract
Purpose: :
According to the 'stem cell origin of cancer' hypothesis, tissue-resident stem cells could give rise to cancer. Tumors would then be composed ot different populations: a rare population of "cancer stem cells (CSCs)" and more differentiated tumor cells. This study investigates expression and distribution of stem cell markers in uveal melanoma.
Methods: :
A total of 8 cell lines established from primary and metastatic uveal melanomas were cultured and subjected to flow cytometric (FACS) and PCR analysis of hematopoietic and stem cell markers, such as CD133, CD34, c-kit, nestin, bcrp-1, CXCR-4, CD44, VEGFR-2, Pax6, Musashi-1, and Sox-2. In addition, 8 paraffin-embedded uveal melanoma specimens were analyzed by immunohistochemistry (IHC) and immunofluorescence (IF) for CD133, Pax6, Musashi-1, nestin, and Sox2 expression.
Results: :
As revealed by FACS analysis, all cell lines were positive for nestin, CD44 and c-kit. Only one cell line also exhibited a small population of CD133-positive cells. Using PCR analysis, different c- and n-terminal isoforms of CD133 were found to be expressed in all the cell lines. Transcripts for nestin, Sox2 and Musashi-1 was also found to be present in all cell lines. IHC and IF unveiled expression of the mentioned stem cell markers by single cells diffusely distributed throughout uveal melanoma.
Keywords: melanoma • immunohistochemistry • gene/expression