Prognostic significance of L1CAM expression in addition to ProMisE in endometrial cancer

To investigate the prognostic significance of L1 cell-adhesion molecule (L1CAM), β-catenin, and programmed death-ligand 1 (PD-L1) in endometrial cancer (EC) patients, with a focus on p53 wild-type subgroup, for additional risk stratification. This retrospective cohort study included EC patients classified according to Proactive Molecular Risk Classifier for Endometrial Cancer (ProMisE) who underwent primary surgical treatment at the single center between January 2014 and December 2018. Immunohistochemical staining was performed for four mismatch repair (MMR) proteins, p53, L1CAM, β-catenin, and PD-L1. DNA polymerase epsilon (POLE) mutation was detected by hot spot sequencing via droplet digital polymerase chain reaction. Survival outcome of each subgroup of L1CAM, β-catenin, and PD-L1 was measured according to their expression. A total of 162 EC patients were included. Endometrioid histologic type and early-stage disease were 140 (86.4%) and 109 (67.3%), respectively. ProMisE classification assigned 48 (29.6%), 16 (9.9%), 72 (44.4%), and 26 (16.0%) patients to MMR-deficient, POLE-mutated, p53 wild-type, and p53 abnormal subgroups, respectively. L1CAM was identified as an independent poor prognostic factor for progression-free survival (PFS; adjusted hazard ratio [aHR], 3.207; 95% confidence interval (CI), 1.432–7.187; P = 0.005), whereas β-catenin and PD-L1 positivity were not associated with recurrence (P = 0.462 and P = 0.152, respectively). In p53 wild-type subgroup, L1CAM positivity was associated with worse PFS (aHR, 4.906; 95% CI, 1.685–14.287; P = 0.004). L1CAM positivity was associated with poor prognosis in EC and further stratified the risk of recurrence in p53 wild-type subgroup, whereas β-catenin and PD-L1 were not informative for risk stratification. •L1CAM was an independent poor prognostic factor for progression-free survival (PFS) in endometrial cancer (EC) patients.•L1CAM positivity was associated with worse PFS in p53 wild-type EC patients, whereas β-catenin and PD-L1 positivity were not.•L1CAM is a potential biomarker for identifying high-risk p53 wild-type EC patients and guiding clinical decision-making.