Unformatted text preview: lial cells of the blood vessels served as an internal positive control [250,251]. In naevi samples MCAM expression was observed in specific areas, mainly in nests of cells in the dermal component of the naevus and only a small proportion (14.7%) of a PAX3‐positive cells were MCAM‐positive (Figure 3.5B, E). Compared to naevi, primary melanomas showed MCAM expression in a larger proportion of PAX3‐positive cells, 56.4% (Figure 3.5B, E), which are again primarily located in the dermal component of the lesion. Samples of melanoma metastases showed MCAM expression in the majority (93.2%) of PAX3‐positive cells (Figure 3.5B, E). In general, MCAM co‐expressed with PAX3 in all MCAM‐positive samples. In accordance with previous reports , number of MCAM expressing PAX3‐
positive cells increased with malignant and particularly metastatic transformation. The expression of MCAM in follicular melanocytes, in contrast to the absence of expression in epidermal melanocytes, highlights again the difference between these two melanocyte populations. 65 Chapter III – Medic and Ziman, 2010 Figure 3.5. Coexpression of PAX3 with markers of cell survival and migration in melanocytic and melanoma cells. A) Double immunofluorescent staining showing PAX3 (mouse monoclonal antibody, DSHB) and BCL2L1 co‐expression in representative samples of normal skin, naevus, primary melanoma and melanoma metastasis. B) PAX3 (mouse monoclonal antibody, DSHB) and MCAM co‐expression in normal skin (epidermal melanocytes), naevus, primary melanoma and melanoma metastasis. Lines in (A) and (B) demarcate epidermal‐dermal border (EDB) or epidermal surface (ES). C) In contrast to the epidermal melanocytes, some PAX3‐positive melanocytes in the outer root sheath (ORS) co‐express MCAM. D) Graph showing overall number of PAX3, BCL2L1 double‐
labelled cells in normal skins, naevi, primary melanomas and melanoma metastases. Each column represents a percentage of PAX3‐positive cells that are also BCL2L1‐positive, averaged across all samples. E) Graph sho...
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