CTLA4 and neoplasm: Hypothesizing that CTLA-4 is a candidate prognostic biomarker for inclusion in a NSCLC Immunoscore, we aimed to explore the prognostic impact of CTLA-4 in tumor epithelial and stromal cells of PTs from 536 resected stage I-IIIA NSCLC patients as well as in 142 matched lymph node metastases (LN+).