[Clinical value of the CA 19-9 tumor marker with special reference to the Lewis phenotype]

Abstract

Background: Because of structure and biosynthesis of CA 19-9, it was postulated that patients with the Lewis phenotype Le(a-b-) are not able to synthesize CA 19-9. But some patients with Le(a-b-) on red blood cells showed elevated levels of this tumor marker.

Patients and method: In 164 patients suffering from benign or malignant diseases both CA 19-9 and the Lewis phenotype were determined in sera. In addition in 51 patients red blood cells were tested for Lewis substances.

Results: The frequencies of the different Lewis phenotypes on red blood cells were compared with the results found in sera. The prevalence of the phenotype Le(a-b-) on erythrocytes was significantly higher than in sera. In 51 patients both determinations were performed. These results were compared additionally. The phenotype Le(a-b-) found on red blood cells agreed with the results found in sera only in 30% of the cases. A loss of Lewis substances on erythrocytes could be seen both in malignant and benign diseases. Only in patients with Lewis substances found in sera elevated levels of CA 19-9 could be seen.

Conclusion: Considering only the Lewis phenotype in sera, it could be confirmed that patients with the genotype Le(a-b-)are not able to express elevated concentrations of CA 19-9.