[Gangliosides GM3 and GD3 in human stomach and breast tumors]

Gangliosides of human gastric and mammary tumours and of homologous normal tissues were studied by using biochemical methods and specific antisera. It was found that in most cases GM3, GD3 and GM1 are predominant gangliosides, whereas several polar components are minor ones. A comparison of the relative amount of ganglioside fractions revealed that in gastric tumours the per cent content of polar compounds is higher than in intact tissue; however, the absolute content of all gangliosides is markedly increased. A comparative study of the composition of mammary tumour and normal tissue gangliosides demonstrated two types of changes: i) the absolute content of all gangliosides in tumour tissue was increased and, ii) the increase in the content of total gangliosides was paralleled with the appearance of a new fraction (presumably GM4), the decrease of the GD3 content and the disappearance of polar gangliosides. A possible mechanism of this effect is discussed.