RESUMEN
AIM: To confirm that the carbohydrate antigen 19.9 (CA 19.9) protein can be evaluated by determining changes in the ß2 zone in protein electrophoresis. MATERIALS AND METHODS: A total of 75 patients (64 with cancer, 11 with benign diseases) with abnormal serum CA 19.9 level were included. RESULTS: Patients with cancer had significantly higher serum CA 19.9 concentrations than those with benign diseases (p<0.001). Similar CA 19.9 levels were observed in patients with normal (median 1129 U/ml), weakly positive (median 699 U/ml) and positive (2333 U/ml) ß2 fraction in protein electrophoresis. In contrast, changes in the protein pattern of the ß2 fraction were related to an inflammatory pattern with significantly higher C-reactive protein concentration (p<0.0001), independently of serum CA 19.9 level. CONCLUSION: The intensity of the ß2 fraction in protein electrophoresis is related to inflammation and not to CA 19.9 in patients with cancer or other diseases.
Asunto(s)
Biomarcadores de Tumor/sangre , Antígeno CA-19-9/sangre , Neoplasias/sangre , Neoplasias/diagnóstico , Adulto , Anciano , Anciano de 80 o más Años , Proteína C-Reactiva/análisis , Electroforesis , Femenino , Humanos , Inflamación , Antígenos del Grupo Sanguíneo de Lewis , Masculino , Persona de Mediana Edad , FenotipoRESUMEN
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.