Genomic and clinical characterization of pediatric lymphoepithelioma-like carcinoma

Pediatric lymphoepithelioma-like carcinoma (pLELC) is a rare neoplasm with unclear prognosis, genome, and tumor microenvironment. Our study aims to elucidate its genomic and clinical characteristics. Forty-one pLELC patients were enrolled at Sun Yat-sen University Cancer Center from 2012 to 2023. Kaplan-Meier analysis was utilized to estimate progression-free survival (PFS) and overall survival (OS). Baseline plasma protein levels from 16 patients and 9 health controls were analyzed using a Olink proteomic platform and whole exon sequence (WES) was performed on 11 tumor samples from 10 pediatric patients. Immunohistochemistry (IHC) for PD-L1was performed, and the infiltration of CD4 or CD8 T cells was evaluated. Patients receiving anti PD-1 in combination with chemotherapy had a 1-year PFS of 100%, while the 2-year PFS was 72.92% (95%CI: 46.80‒100%). The 1-year OS for patients receiving anti PD-1 in combination with chemotherapy was 100%, and the 2-year OS was 87.5% (95%CI: 67.34-100%). Significant upregulation of immune checkpoint molecules was detected including LAG-3, PD-L1, and galectin-9 in LELC group by proteomic analysis (P