AUTHOR=Striefler Jana Käthe , Riess Hanno , Lohneis Philipp , Bischoff Sven , Kurreck Annika , Modest Dominik Paul , Bahra Marcus , Oettle Helmut , Sinn Marianne , Bläker Henrik , Denkert Carsten , Stintzing Sebastian , Sinn Bruno Valentin , Pelzer Uwe TITLE=Mucin-1 Protein Is a Prognostic Marker for Pancreatic Ductal Adenocarcinoma: Results From the CONKO-001 Study JOURNAL=Frontiers in Oncology VOLUME=Volume 11 - 2021 YEAR=2021 URL=https://www.frontiersin.org/journals/oncology/articles/10.3389/fonc.2021.670396 DOI=10.3389/fonc.2021.670396 ISSN=2234-943X ABSTRACT=Background: The Mucin-family protein, MUC1 impacts on carcinogenesis and tumour invasion. We evaluated the impact of MUC1 expression on outcome in a cohort of 158 patients with resected pancreatic ductal adenocarcinomas (PDAC) in the CONKO-001 study (adjuvant gemcitabine [gem] vs. observation [obs]). Methods: The percentage of MUC1-positive tumour cells by immunohistochemistry (IHC) and the staining intensity were evaluated by 2 observers blinded to outcome. The numeric values of both parameters were multiplied, resulting in an immunoreactivity score (IRS) ranging from 0 to 12. Low versus high MUC1 expression was defined based on data distribution (IRS 0-4 vs IRS >4). Outcomes in terms of disease-free (DFS) and overall survival (OS) were evaluated by Kaplan-Meier method, log-rank tests and Cox regressions. Results: In total, tumours of 158 study patients were eligible for immunohistochemistry of MUC1. High cytoplasmic MUC1 expression was associated with impaired DFS and OS in the overall study population (hazard ratio (HR) for DFS: 0.49, 95% CI 0.31 to 0.78, p=.003; HR for OS: 0.46, 95% CI 0.29 to 0.73, p=.001). In the study arms, prognostic effects of MUC1 were also evident in the observation group (HR for DFS: 0.55; 95% CI 0.29 to 1.04, p=.062; HR for OS: 0.34, 95% CI 0.17 to 0.67, p=.001) and trending in the gem group (HR for DFS: 0.48, 95% CI 0.24 to 0.95, p=.041; HR for OS: 0.56, 95% CI 0.28 to1.11, p=.093). Conclusion: Our data suggest that MUC1 expression is a powerful prognostic marker in patients with PDAC after curatively intended resection.