The Presence of CA19‐9 in Serum and Saliva from Lewis Blood‐group Negative Cancer Patients

Abstract

Eighteen cancer patients showed high levels of CA19-9 in sera, even though the blood-group phenotypes of their red blood cells were Le(a-b-). Seven of these patients (group I) were determined as Le(a-b-) from both red blood cells and saliva consistently, whereas eleven other patients (group II) secreted either Lea or Leb antigen in saliva and showed the expression of incompatible Lewis blood-group antigens. GDP-fucose:N-acetyl-glucosaminide .alpha.(1 .fwdarw. 4)-L-fucosyltransferase was demonstrated to be present in salivas from both group I and group II. These results suggest that a cancer-associated alteration of Lewis blood-group antigen expression occurs in cancer patients.