PT  - JOURNAL ARTICLE
AU  - MARINA PARRA-ROBERT
AU  - VÍCTOR MOLINA SANTOS
AU  - SILVIA MIRÓ CANIS
AU  - XAVIER FILELLA PLA
AU  - JOSEP MARIA AUGÉ FRADERA
AU  - RAFAEL MOLINA PORTO
TI  - Relationship Between CA 19.9 and the Lewis Phenotype: Options to Improve Diagnostic Efficiency
AID  - 10.21873/anticanres.12931
DP  - 2018 Oct 01
TA  - Anticancer Research
PG  - 5883--5888
VI  - 38
IP  - 10
4099  - http://ar.iiarjournals.org/content/38/10/5883.short
4100  - http://ar.iiarjournals.org/content/38/10/5883.full
SO  - Anticancer Res2018 Oct 01; 38
AB  - Background/Aim: Approximately 10% of patients are unable to synthesize CA 19.9 (Lewis-negative), and these results are erroneously considered false-negatives. The aim of this study was to confirm that CA 19.9 cannot be detected by immunoassays in Lewis-negative patients. Materials and Methods: CA 19.9 levels were measured by immunological assays and Lewis phenotype was determined by the haemagglutination reaction. Results: Patients with Lewis phenotype (a+b−) or (a−b+) had significantly higher CA 19.9 levels than Lewis-negative patients with active cancer (p<0.001), no-evidence of disease (NED) patients (p<0.001) or patients with benign disease (p<0.001). Ninenty-four percent of patients (33/35) with undetectable CA 19.9 had a Lewis-negative phenotype. Additionally, 94.7% (34/36) of patients with Lewis-negative phenotypes had undetectable CA 19.9 serum levels. Conclusion: Patients with undetectable CA 19.9 serum levels tend to be Lewis-negative, and CA 19.9 is not useful in diagnosis or follow-up.