The present invention refers to compounds of formula (I) as useful melanoma vaccines active ingredients. As a matter of fact, compounds of formula (1) are immunogenic artificial antigens, mimetics of GM3 and GM3 lactone, well known tumor associated antigens (TAAs). In addition, the present invention refers to specific antibodies for compounds of formula (I) which are able to bind to the TAAs. The hereinabove reported compounds and antibodies are therefore potentially useful respectively for the active and passive immunization against tumors over-expressing GM3 ganglioside, in a preferred embodiment melanoma and colon cancer, and for their diagnosis and prognosis.