FUT6 and colonic neoplasm: In a recent review [20], we have proposed that the right question to answer is not “why are sLex levels high in colon cancer?” but rather “why are sLex levels low in the normal colon?” Competition between FUT6 and enzymes synthesizing alternative structures, such as Siaα2,3(GalNAcβ1,4)Galβ1,3/4GlcNAc (the Sda antigen) [21,22] or the sialyl 6-sulfo-Lewis x antigen [23] has been proposed.