Baseline blood immunological profiling differentiates between Her2-breast cancer molecular subtypes: implications for immunomediated mechanisms of treatment response.

Breast cancer patients' response to treatment is highly dependent on the primary tumor molecular features, with triple-negative breast tumors having the worst prognosis of all subtypes. According to the molecular features, tumors stimulate the microenvironment to induce distinct immune responses, baseline immune activation being associated with higher likelihood of pathologic response. In this study, we investigated the deconvolution of the immunological status of triple-negative tumors in comparison with luminal tumors and the association with patients' clinicopathological characteristics. Gene expression of 84 inflammatory molecules and their receptors were analyzed in 40 peripheral blood samples from patients with Her2- primary breast cancer tumors. We studied the association of triple-negative phenotype with age, clinical stage, tumor size, lymph nodes, and menopausal status. We observed that more patients with estrogen (ER)/progesterone (PR)-negative tumors had grade III, while more patients with ER/PR-positive tumors had grade II tumors. Gene expression analysis revealed a panel of 14 genes to have differential expression between the two groups: several interleukins: IL13, IL16, IL17C and IL17F, IL1A, IL3; interleukin receptors: IL10RB, IL5RA; chemokines: CXCL13 and CCL26; and cytokines: CSF2, IFNA2, OSM, TNSF13. The expression levels of these genes have been previously shown to be associated with reduced immunological status; indeed, the triple-negative breast cancer patients presented with lower counts of lymphocytes and eosinophils than the ER/PR-positive ones. These results contribute to a better understanding of the possible role of antitumor immune responses in mediating the clinical outcome.