[Usefulness of sialic acid as a tumor marker]

In order to analyze the utility of sialic acid as a tumor mass marker, its levels have been determined in 253 neoplastic patients, 57 patients with non-tumoral pathology and 60 healthy controls. Significant differences in the sialic acid values were observed between the control group and the rest (p less than 0.001). When the neoplastic patients were studied according to the extension of their disease, we found that the SA levels in patients under complete remission were significantly lower than in the other stages (p less than 0.01) and that patients in stage IV presented the highest levels (p less than 0.05). Differences between stages I, II and III were not detected. Furthermore, no differences were observed regarding either the type of neoplasia or if the patients had or did not have tumor pathology. We conclude that sialic acid is a tumor marker with poor specificity that grossly relates with the tumor size.