There was a link to SSEA1, since two papers had been published showing that the molecularly undefined murine “F9 antigen” could be serologically detected in cultures of human teratocarcinomas and inferring that human EC cells were also marked by the “F9 antigen”.[9, 10] I therefore started our work on the human lines assuming that human EC cells would also express SSEA1. This evidence concerns the gene FUT4 and teratocarcinoma.