Adecrease in the level ofO-acetylatedsialicacidsobserved in colorectal carcinoma may lead to an increase in the expres-sion of sialyl Lewis X , a tumor-associated antigen, which is related toprogressionof colorectal cancer tometastasis. The underlyingmechanism for this reduction is, however, not fully understood. Two enzymes are thought to be primarily responsible for the turnover of O-acetyl ester groups on sialic acids; sialate-O-acetyltransferase (OAT) and sialate-O-acetylesterase (OAE).
