L1CAM and cancer: To our knowledge, A1[3]G(4)2 structure [Galβ1-4Galβ1-4GlcNAcβ1-2Manα1-3(Manα1-6)Manβ1-4GlcNAcβ1GlcNAc] of L1CAM acetylated on sialic acid is the first cancer biomarker related to metabolic replacement of Neu5Ac with the immunogenic dietary NeuGc molecule in protein-linked N-glycans.