Relationship Between CA 19.9 and the Lewis Phenotype: Options to Improve Diagnostic Efficiency

Reduced and Normalized Carbohydrate Antigen 19-9 Concentrations after Neoadjuvant Chemotherapy Have Comparable Prognostic Performance in Patients with Borderline Resectable and Locally Advanced Pancreatic Cancer

“…However, elevated CA 19-9 has also been associated with other gastrointestinal tumors, as well as with biliary tract inflammation. Moreover, 5-10% of patients with PDAC are Lewis antigen negative, with normal CA 19-9 concentrations [11]. CA 19-9 concentration after NACT may be a biologic marker in patients with BRPC and LAPC because normalized or reduced CA 19-9 concentration after NACT has been reported to be an important prognostic marker of better OS and RFS [17].…”

“…However, prognostic markers for responders to NACT have not yet been identified except circulating tumor cell or DNA [8]. Although several studies found that normalization of carbohydrate antigen (CA) 19-9 concentration is associated with better patient prognosis [9], 5-10% of patients with PDAC have normal CA 19-9 at diagnosis because of a Lewis-negative phenotype, and waiting until normalization of CA 19-9 is difficult in real-world practice [10,11]. This study investigated the ability of reduced CA 19-9 rather than normalized CA 19-9 after NACT to predict oncologic outcomes in patients with BRPC or LAPC.…”

AGA Clinical Practice Update on Surveillance for Hepatobiliary Cancers in Patients With Primary Sclerosing Cholangitis: Expert Review

“…18 Importantly, expression of CA19-9 requires the presence of the Lewis blood group antigen, which is lacking in up to 10% of the population. 23 In addition, genotypic variants of fucosyltransferases 2 and 3 influence levels of CA19-9, and utilization of different cut-off values based on fucosyltransferase 2 and 3 genotype may improve the tumor marker sensitivity. 24 Imaging studies allow noninvasive evaluation of the biliary tree, however, when used alone, sensitivity and specificity are suboptimal.…”

Biliary endoscopy in the management of primary sclerosing cholangitis and its complications

“…due to mutations in FUT3, the gene encoding fucosyltransferase 3 cannot effectively secrete CA 19-9, and thus will not mount elevated CA 19-9 levels even in the presence of CCA or other pancreatobiliary malignancy. 53-55 Thus, the serum CA 19-9 level should be interpreted cautiously, and an undetectable level in the presence of (benign or malignant) biliary obstruction should be regarded as a possible clue to an individual patient’s inability to synthesize CA 19-9. 53…”

“…53-55 Thus, the serum CA 19-9 level should be interpreted cautiously, and an undetectable level in the presence of (benign or malignant) biliary obstruction should be regarded as a possible clue to an individual patient’s inability to synthesize CA 19-9. 53…”