Subtype-specific prognostic impact of different immune signatures in node-negative breast cancer.

BACKGROUND: The role of different subtypes of immune cells is still a matter of debate. METHODS: We compared the prognostic relevance for metastasis-free survival (MFS) of a B-cell signature (BS), a T-cell signature (TS), and an immune checkpoint signature (CPS) in node-negative breast cancer (BC) using mRNA expression. Microarray-based gene-expression data were analyzed in six previously published cohorts of node-negative breast cancer patients not treated with adjuvant therapy (n = 824). The prognostic relevance of the individual immune markers was assessed using univariate analysis. The amount of independent prognostic information provided by each immune signature was then compared using a likelihood ratio statistic in the whole cohort as well as in different molecular subtypes. RESULTS: Univariate Cox regression in the whole cohort revealed prognostic significance of CD4 (HR 0.66, CI 0.50-0.87, p = 0.004), CXCL13 (HR 0.86, CI 0.81-0.92, p < 0.001), CD20 (HR 0.76, CI 0.64-0.89, p = 0.001), IgκC (HR 0.81, CI 0.75-0.88, p < 0.001), and CTLA-4 (HR 0.67, CI 0.46-0.97, p = 0.032). Multivariate analyses of the immune signatures showed that both TS (p < 0.001) and BS (p < 0.001) showed a significant prognostic information in the whole cohort. After accounting for clinical-pathological variables, TS (p < 0.001), BS (p < 0.05), and CPS (p < 0.05) had an independent effect for MFS. In subgroup analyses, the prognostic effect of immune cells was most pronounced in HER2+ BC: BS as well as TS showed a strong association with MFS when included first in the model (p < 0.001). CONCLUSION: Immune signatures provide subtype-specific additional prognostic information over clinical-pathological variables in node-negative breast cancer.

Prognostic significance of interferon regulating factor 4 (IRF4) in node-negative breast cancer.

PURPOSE: The transcription factor IRF4 regulates immunoglobulin class switch recombination as well as plasma cell differentiation. We examined the prognostic significance of IRF4 expression in node-negative breast cancer (BC). METHODS: IRF4 expression was evaluated by immunostaining in a cohort of 197 node-negative BC patients not treated in adjuvant setting, referred to as Mainz cohort. The prognostic significance of immunohistochemically determined IRF4 expression for metastasis-free survival (MFS) was examined by Kaplan-Meier survival analysis as well as univariate and multivariate Cox analysis adjusted for age, pT stage, histological grade, ER, and HER2 status. For verification of immunohistochemical results, IRF4 mRNA expression was evaluated using microarray-based gene expression profiling in four previously published cohorts (Mainz, Rotterdam, Transbig, Yu) consisting of 824 node-negative breast cancer patients in total, who were not treated with adjuvant therapy. The prognostic significance of IRF4 mRNA expression on metastasis-free survival (MFS) was examined by univariate and multivariate Cox analysis in the Mainz cohort and by a meta-analysis of all node-negative BC patients and different molecular subtypes. IRF4 mRNA levels were compared to immunohistochemically determined IRF4 expression in 140 patients of the Mainz cohort using Spearman correlation. RESULTS: Immunohistochemically determined high IRF4 expression was associated with higher MFS in univariate Cox regression (HR 0.178, 95% CI 0.070-0.453, p < 0.001). IRF4 maintained its significance independently of established clinical factors for MFS (HR 0.088, 95% CI 0.033-0.232, p < 0.001). Immunohistochemically, determined IRF4 correlated moderately with IRF4 mRNA expression (ρ = 0.589). Higher expression of IRF4 was associated with better MFS in a meta-analysis of the total cohort (HR 0.438, 95% CI 0.307-0.623, p < 0.001). Prognostic significance was more pronounced in the HER2+ molecular subtype (HR 0.215, 95% CI 0.090-0.515, p = 0.001) as compared to the luminal A (HR 0.549, 95% CI 0.248-1.215, p = 0.139), luminal B (HR 0.444, 95% CI 0.215-0.916, p = 0.028), and basal-like subtypes (HR 0.487, 95% CI 0.269-0.883, p = 0.018). Further, IRF4 expression showed independent prognostic significance in a multivariate analysis of the Mainz cohort (HR 0.236, 95% CI 0.105-0.527, p < 0.001). CONCLUSIONS: IRF4 had independent prognostic significance in node-negative BC. Higher expression of IRF4 was associated with improved outcome. The prognostic impact differed between diverse molecular subtypes and was most pronounced in HER2+ breast cancer.