 Elevated levels of cell membrane sialylation are associated with increased cancer cell potential for invasion and metastasis and with progression of the malignancy.Some sialylation inhibitors can make cancer cells less malignant.One possible explanation for the relationship between increased sialylation and a malignant phenotype is that sialylation results in a thick layer of coating on the cell membrane that masks cancer antigens and protects malignant cells from immune surveillance.