Expression of lymphoid structure-associated cytokine/chemokine gene transcripts in tumor and protein in serum: Outcomes for patients with melanoma.

Abstract

9565 Background: Proinflammatory chemokines/cytokines support development and maturation of tertiary lymphoid structures (TLS) within the tumor immune microenvironment (TIME). In the current study, we sought to investigate the prognostic value of TLS-associated chemokine/cytokine (TLS-kine) expression levels in melanoma patients (MEL PTs) by performing serum protein and tissue transcriptomic analyses, and to then correlate these data with PT tumor clinicopathological and TIME characteristics. Methods: Levels of TLS-kines in PT sera were quantitated using a custom Luminex Multiplex Assay. The Cancer Genomic Atlas MEL cohort (TCGA-SKCM) and a Moffitt MEL cohort were used for tissue transcriptomic analyses. Associations between target analytes and survival outcomes, clinicopathological variables, and correlations between TLS-kines were statistically analyzed. Results: Serum of 95 PTs with MEL were evaluated; 48 (50%) female, median age of 63, IQR 51-70 years. Serum levels of APRIL/TNFSF13 were positively correlated with levels of both CXCL10 and CXCL13. Tumors with brisk/non-brisk tumor-infiltrating lymphocytes (TIL) vs. absence of TIL exhibited significantly higher levels of APRIL/TNFSF13 (p = 0.01), CCL19 (p = 0.01) and CXCL13 (p = 0.01). In multivariate analyses, high levels of serum APRIL/TNFSF13 were associated with improved event-free survival after adjusting for age and stage (HR = 0.64, 95% CI 0.43-0.95; p = 0.03). High expression of APRIL/TNFSF13 transcripts was significantly associated with improved OS in TCGA-SKCM[n = 448](HR = 0.69, 95% CI 0.52-0.93; p = 0.01) and in Moffitt MEL PTs [n = 134] (HR = 0.51, 95% CI: 0.32-0.82; p = 0.006). Further incorporation of CXCL10 and CXCL13 transcript levels in a 3-gene index revealed that high APRIL/CXCL10/CXCL13 expression was associated with improved OS in the TCGA SKCM cohort (HR = 0.42, 95% CI 0.19-0.94; p = 0.035). High coordinate expression of the TNFSF13/CXCL10/CXCL13 transcripts in MEL was correlated with an increased presence of naïve B cells, plasma B cells, CD8+ T cells, and M1 macrophages and decreased levels of M2 macrophages and mast cells as well as a reduced neural network gene signature. Conclusions: Serum protein and tumor transcript levels of APRIL/TNFSF13 are associated with improved survival outcomes. PTs exhibiting high coordinate expression of APRIL/CXCL10/CXCL13 transcripts in their tumors displayed superior OS. MEL differentially expressed genes positively associated with high coordinate APRIL/CXCL10/CXCL13 expression were linked to tumor infiltration by a diverse array of proinflammatory immune cell types. Further investigation of TLS-kine expression profiles related to clinical outcomes is warranted.