{"entity":{"id":"paper-yeh-ca19-9-lewis-negative-fut3-cutoff-ccr-2026","kind":"paper","name":"A new CA19-9 cutoff value identifies Lewis antigen status and refines prognostic stratification in PDAC","aka":[],"tldr":"Genotyping 615 patients showed that about one in ten cannot make CA 19-9, that their outlook is as poor as patients with very high readings, and that a value of 7 or below is a practical way to spot them without a genetic test.","summary":"Germline whole-exome sequencing in a multicentre cohort of 615 patients with pancreatic ductal adenocarcinoma determined FUT2 and FUT3 genotypes. Receiver operating characteristic analysis identified the optimal CA 19-9 cut-off for FUT3-null status and maximally selected rank statistics derived cut-offs stratifying overall survival in a training set (307) tested in a validation set (308). FUT3-null patients had similar demographics but a much lower median baseline CA 19-9 (2.4 against 496 U/mL) and a median overall survival of 13.5 months, comparable with FUT3-intact patients above 200 U/mL (12.9 months). A cut-off of 7 U/mL identified FUT3-null status with positive predictive value 95.1% and accuracy 87.9%. Using 7 and 200 U/mL without genotyping gave four prognostic groups: above 7 to 37 (23.2 months), above 37 to 200 (22 months), above 200 (12.8 months) and 7 or below, likely FUT3-null (13.5 months).","asOf":"2026-09-24","links":[{"label":"Yeh et al., Clin Cancer Res 2026: FUT3-null (Lewis-negative) patients and a CA 19-9 cut-off in 615 patients","url":"https://doi.org/10.1158/1078-0432.ccr-25-4564"},{"label":"PubMed","url":"https://pubmed.ncbi.nlm.nih.gov/42162970/"}],"tags":[],"related":[],"cancers":["pancreatic"],"sections":[],"technologies":["germline-testing"],"targets":[],"drugs":[],"companies":[],"institutions":[],"pathways":[],"terms":["ca19-9","founder-mutation"],"trials":[],"people":[],"bottlenecks":[],"keyPapers":[],"journals":["clinical-cancer-research"],"dependsOn":[],"notes":[],"journal":"Clinical Cancer Research","year":2026,"doi":"10.1158/1078-0432.ccr-25-4564","pmid":"42162970","authors":"Yeh CM, Yu CC, Lee AF, et al.","paperType":"observational","findings":["About 10% of patients are FUT3-null non-producers with median CA 19-9 2.4 against 496 U/mL.","CA 19-9 of 7 U/mL or below identifies them with 95.1% positive predictive value.","Non-producers have the same poor survival as patients above 200 U/mL."],"whatItMeans":"A very low CA 19-9 is not reassurance: it marks the non-producer group whose outlook matches the highest-marker group, and it gives clinics a rule they can apply without genotyping.","caveats":["Taiwanese multicentre cohort; the 10% non-producer share varies by ancestry.","Retrospective derivation and validation within one cohort."],"changedPractice":false,"participants":615},"route":"/key-papers/paper-yeh-ca19-9-lewis-negative-fut3-cutoff-ccr-2026/","neighbours":{"cancer":[{"id":"pancreatic","kind":"cancer","name":"Pancreatic ductal adenocarcinoma","route":"/cancers/pancreatic/"}],"technology":[{"id":"germline-testing","kind":"technology","name":"Germline (hereditary) testing","route":"/technologies/germline-testing/"}],"term":[{"id":"ca19-9","kind":"term","name":"CA 19-9","route":"/terms/ca19-9/"},{"id":"founder-mutation","kind":"term","name":"Founder mutation (BRCA1 185delAG and 5382insC, BRCA2 6174delT)","route":"/terms/founder-mutation/"}],"journal":[{"id":"clinical-cancer-research","kind":"journal","name":"Clinical Cancer Research","route":"/journals/clinical-cancer-research/"}]}}