[Behavior of serum sialic acid levels at various stages of neoplastic disease].

Serum sialic acid levels were measured at two different stages of neoplasia (active and non-active phases). CEA levels were also assayed at the same time. 98 patients suffering from different neoplastic diseases and a group of healthy controls were studied. Serum sialic acid levels were always significantly higher in the neoplastic patients. When neoplastic disease were divided into active and non-active groups, it was observed that the level of this glycoprotein was specific in the non-active (NA) phase only for breast tumours and lymphomas. Correlation with CEA levels was also significant in these cases. It is concluded that serum sialic acid assay may be useful only for melanomas, breast tumours and lymphomas where the level of this membrane protein undergoes significant changes according to the stage of the tumour.