g(m3)-ganglioside and Nevus--Pigmented

The aim of this study was to determine the expression of N-Glycolyl GM3 (NeuGcGM3) ganglioside in oral mucosal melanomas.. To assess the presence of cytidine monophospho-N-acetylneuraminic acid hydroxylase (CMAH) mRNA, an RT-PCR assay was performed in melanoma cell line (ME), an oral mucosal ME, and two fresh oral mucosal melanoma tissues. Expression of NeuGcGM3 ganglioside was evaluated by immunohistochemistry in 44 primary oral mucosal melanomas and 10 oral melanotic nevi. Also, the expression of NeuGcGM3 was examined in ME by immunocytochemistry.. We first checked the expression of CMAH in ME and two fresh oral mucosal melanoma tissues. Presence of NeuGcGM3 ganglioside was evident in 37 of 44 cases (84.1%), showing a diffuse cytoplasmic and membranous staining. Patients with primary occurrence showed high levels of NeuGcGM3 ganglioside compared to patients with secondary occurrence. On the other hand, negative immunoreaction was evidenced in oral melanotic nevi. ME also presented the expression of NeuGcGM3 by immunocytochemistry.. In this work, we for the first time evaluated the expression of 14F7 MAb immunorecognition in oral mucosal melanomas. Our results were in agreement with the assumption that NeuGcGM3 ganglioside may be considered as target for passive and active immunotherapy in oral mucosal melanomas expressing this molecule and indicate less risk of recurrence and a better prognosis. Moreover, ME provides a platform for more studies on the specific function of NeuGcGM3 in oral mucosal melanomas.

Topics: Antibodies, Monoclonal; Cell Line, Tumor; Cell Membrane; China; Cytoplasm; Female; G(M3) Ganglioside; Humans; Immunoglobulin G; Immunohistochemistry; Male; Melanoma; Middle Aged; Mixed Function Oxygenases; Mouth Mucosa; Mouth Neoplasms; Neoplasm Recurrence, Local; Nevus, Pigmented

The expression of gangliosides in non-malignant tissues (epidermis and pigmented nevus) and neoplastic lesions (melanoma, squamous cell carcinoma [SCC] and basal cell carcinoma [BCS]) of the human skin was analyzed immunohistochemically and biochemically to characterize the features associated with malignancy. Immunohistochemical staining with an anti-II3NeuAc-LacCer (GM3) monoclonal antibody (M2590 mAb) and an anti-II3(NeuAc)2-LacCer (GD3) mAb (R24) showed the expression of the gangliosides GM3 and GD3 to vary among the different tissues. M2590 clearly stained epidermal keratinocytes and the tumor cells of BCC and SCC, and strongly stained melanocytes and melanoma cells. In contrast, R24 did not stain epidermal keratinocytes and only faintly stained SCC cells, while it clearly stained BCC cells, and intensely stained melanocytes and melanoma cells. GM3 showed a similar level of staining among the tissue specimens, while the level of GD3 staining was quite variable among the tumor specimens. Biochemical analysis by thin-layer chromatography (TLC) with resorcinol staining and TLC immunostaining with either M2590 or R24 showed both GM3 and GD3 to be commonly expressed by both the normal and malignant skin tissues, including SCC. There was no close correlation between the intensity of immunohistochemical staining and the biochemically detected amounts of these gangliosides. This may have been partly due to the so-called cryptic expression of cell membrane gangliosides. Our results thus suggest that analysis of the tumor-associated expression of gangliosides requires several methods, since the sensitivity of the methods used may have a considerable effect on the diagnostic value of gangliosides as skin cancer markers.

Topics: Biomarkers, Tumor; Carcinoma, Basal Cell; Carcinoma, Squamous Cell; Dendritic Cells; Epidermis; G(M3) Ganglioside; Gangliosides; Gene Expression; Humans; Immunoenzyme Techniques; Melanocytes; Melanoma; Nevus, Pigmented; Phenotype; Skin; Skin Neoplasms