Klinische Aussagekraft des Tumormarkers CA 19-9 unter besonderer Berucksichtigung des Lewis-Phanotyps

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.