Female Sex and Increased Immune Marker mRNA Gene Expression are Associated With Decreased Overall Survival in Patients With HPV-Negative Head and Neck Cancer.

PURPOSE/OBJECTIVE(S) Females with HPV-negative head and neck squamous cell carcinoma (HNSCC) have worse outcomes compared to men in The Cancer Genome Atlas (TCGA). Our primary aim was to determine if females have an increased frequency of destructive TP53 mutations and divergent mRNA gene expression of immune markers. Our secondary aim was to determine if females have poor progression-free survival (PFS) and overall survival (OS) after controlling for TP53 mutations, immune markers, and clinicopathologic factors. MATERIALS/METHODS We identified 461 patients in TCGA with non-metastatic HNSCC (stages I-IVB) treated with radiotherapy (RT) +/- chemotherapy (CT) (N = 51) or surgery +/- adjuvant RT and CT (N = 410). We performed descriptive statistics on sex, TP53 mutations, and immune markers. We used Mann-Whitney U and Fisher's exact tests to evaluate differences in continuous log2 transformed mRNA counts for immune markers and the presence of destructive TP53 mutations, respectively. We performed Cox regression on OS and PFS according to sex, presence of destructive TP53 mutations, and a gene signature of immune markers (as a weighted sum of genes). We controlled for demographic and clinicopathologic factors. All tests were two-tailed. Final model was derived from primary covariates and confounders with P-value thresholds of < 0.05 and < 0.10, respectively. Data were extracted using open-source software packages and analyzed using statistical software. RESULTS In females, we observed increased mRNA gene expression of PD1, PDL1, IDO1, CXCL11, TIGIT, and TIM3 (all P-values < 0.05). We did not observe differences in TP53 mutations or L1CAM, SAA1, CTLA4, and LAG3 mRNA gene expression. On adjusted Cox regression for OS, female sex (HR: 1.7, CI: 1.12-1.74, P = 0.01), destructive TP53 mutations (HR: 1.63, CI: 1.03-2.60, P = 0.03), ENE (HR: 2.22, CI: 1.40-3.50, P < 0.001), ≥ four lymph nodes (HR: 1.71, CI: 1.05-2.78, P = 0.03), positive margins (HR: 2.63, CI: 1.51-4.58, P < 0.001), and a signature of immune markers (HR: 2.72, CI: 1.44-5.13, P = 0.002) were all associated with decreased OS. Adjuvant RT (HR: 0.60, CI: 0.36-0.99, P = 0.048) and CT (HR: 0.59, CI: 0.37-0.93, P = 0.02) were associated with increased OS. On adjusted Cox regression for PFS, female sex (HR: 1.36, CI: 1.00-1.87, P = 0.048), ENE (HR: 2.44, CI: 1.78-3.45, P < 0.001), ≥ four lymph nodes (HR: 1.46, CI: 1.04-2.05, P = 0.03), and positive margins (HR: 1.57, CI: 1.07-2.32, P = 0.02) were all associated with decreased PFS. We did not observe covariate interactions in either model. CONCLUSION Females with HPV-negative HNSCC had increased mRNA gene expression of specific immune markers and worse outcomes, even after controlling for relevant factors. Integration of TP53 mutations and immune marker expression may help improve health disparities research in HNSCC. Validation of our findings is ongoing using institutional data.