[Clinical evaluation of serum sialyl SSEA-1 (SLX) in diagnosis of cancers].

In order to evaluate the usefulness of sialyl SSEA-1 (SLX) as a tumor marker of digestive cancers, serum levels of the antigen were determined in 334 patients with malignancies and 196 patients with benign diseases. The results indicated that positivity of the antigen in sera from malignant patients was highest in pancreatic cancer (58%) and biliary tract cancer (56%). False positive incidence of SLX in sera from benign diseases was as low as 6%, revealing low false positivity. Comparison with other tumor markers such as CA19-9, CA-50, CEA and ST-439 showed that positivity of SLX was as high as that of CEA, whereas it was lower than that of CA19-9 or CA-50. On the other hand, false positivity of SLX as well as ST-439 was lowest, and accuracy of SLX was no less high than that of CA19-9 or CA-50. In sera of pancreatic and biliary tract cancer, positive incidences of CA19-9, CEA and ST-439 were 80%, 64% and 53%, respectively, and the diagnostic efficiency increased by combined assay of SLX with CA19-9 (88%), CEA (81%) and ST-439 (71%). SLX appears to be no less useful than the other recently developed carbohydrate antigens or CEA as serum tumor marker for pancreatico-biliary cancer.