To evaluate the acceptor specificities of Gb3/CD77 synthases M and P, we transfected cells of the human 2102Ep teratocarcinoma line (which express large amounts of neutral glycosphingolipids) with vectors encoding M or P. The cells were evaluated using flow cytofluorometry, HPTLC, mass spectrometry, metabolic labeling and Western blotting. This evidence concerns the gene A4GALT and teratocarcinoma.