ACTA ENDOCRINOLOGICA (BUC)

Background. Gangliosides are Nacetyl - neuraminic - acid containing glycosphyngolipids that modulate several\r\ncellular functions.\r\nObjective. The present study confirmed the presence of cellular gangliosides in melanocytic tumors with\r\nneuroectodermal origin. These molecules showed large quantitative and structural variability in melanocytic cells.\r\nMethods. The spectrum and levels of gangliosides were performed from 1991 until 2010, in 411 specimens of melanoma, 108 cutaneous metastases of melanoma, 206\r\nnevocellular and dysplastic nevus and 130 specimens of normal skin.\r\nResults. Melanoma showed aberrant gangliosides expression. This included overexpression of normal ganglioside\r\nconstituents (GM2, GM3, GD2, GD3), which also appear in melanocytic nevus and epidermis tissues, and expression of\r\ngangliosides (O-Acetyl-Ganglioside) not found in normal adult tissue. The ganglioside composition of\r\nmelanoma is: GM1 (1,29?0,87%), GM2 (10,32?4,11%), GM3 (22,23?11,30%), GD2 (16,03?9,13%), GD3 (39,06?14,25%), GD1a\r\n(2,16?0,77%), GD1b (1,74?1,01%), GT1b (1,82?1,11 %), GQ1b (1,34?1,07%), OAcetyl-GD3 (4,01?2,81%).\r\nConclusions. The overexpression and variability of gangliosides in melanoma and the low expression of them in normal tissue was correlated with oncogenic process and\r\nmetastatic potential.

Background. Malignant melanoma is the most aggressive form of skin cancer with a rapidly increasing incidence rate. In contrast to other tumors, the role of sex steroid hormones\r\nin the initiation and progression of melanoma remains unclear.\r\nObjective. To assess the interaction between the content and composition of gangliosides and sex steroid hormones 17&#946;-\r\nestradiol (E2) and testosterone (T) in malignant melanoma.\r\nPatients and methods. The analysis included 45 melanoma patients (age 28-86; 14 men, 15 non -pregnant women in mid\r\nfollicular phase and 16 postmenopausal women) and 46 healthy controls. Serum levels of gangliosides (GM1-3, GD1a,b,2,3, GT1b, GQ1b), estradiol, testosterone measured in serum by chromatographic and immunochemiluminescence methods were correlated with sex and age.\r\nResults. Steroid hormones levels showed no differences between groups (p>0.05), while total gangliosides in normal\r\nserum were significantly lower than total ganglioside concentrations determined in melanoma samples (18.63 ? 3.17 mg/dL versus 74.82 ? 34.56 mg/dL) (p<0.05). There were no differences related to sex or age within groups regarding total gangliosides levels. Gangliosides pattern in\r\nmelanoma patients compared to control showed lower GM3, higher GD3, lower GM3/GD3 ratio, increased GD2 levels, and\r\nno significant variation of GM1, GM2, GD1a, GT1b gangliosides. There is a positive correlation between estradiol levels and total gangliosides concentration both in non-pregnant premenopausal and postmenopausal melanoma patients. GM3 is negatively correlated with estradiol levels in melanoma group, GT1b and O-Acetyl GD3 concentrations are positively correlated with estradiol levels in women with melanoma. Testosterone levels showed no significant\r\ncorrelation with the content and pattern of gangliosides in melanoma patients.\r\nConclusions. The correlations between content and composition of gangliosides and estradiol in melanoma suggest a possible role of these molecules in melanoma behavior.