Immune profiling of oral pre-malignant lesions (OPLs): An Erlotinib Prevention of Oral Cancer (EPOC) study biobank analysis.

1545Background: We previously demonstrated that high-risk loss of heterozygosity (LOH) profiles (i.e., 3p14/9p21 LOH) and EGFR gene copy number gain (CNG) in OPLs were associated with inferior oral cancer-free survival (OCFS) in patients enrolled in the randomized EPOC trial. Herein, we performed comprehensive immune profiling of OPLs and correlated the findings with molecular features and outcomes, using the prospectively collected and clinically annotated EPOC biobank. Methods: We evaluated OPL specimens by multiplex immunofluorescence using the Opal 7-color fIHC Kit and the Vectra multispectral microscope / inForm Cell Analysis software. Markers included AE1/AE3 pancytokeratins, PD-L1 (clone E1L3N), CD3, CD8, and CD68. Wilcoxon rank-sum and Fisher’s exact tests were used to assess the associations between binary markers and continuous and categorical variables, respectively. Cox model was used to investigate associations of markers with OCFS. Results: The cohort included 188 OPL patients with hyperkera...