Interleukin 8 in progression of hormone-dependent early breast cancer

The only way to perceive the real clinical course of disease and the prognostic significance of potential biomarkers is follow-up of patients who did not receive any kind of adjuvant therapy. Many studies have confirmed high levels of interleukin 8 (IL8) in HER2-enriched and basal-like (ER–) primary breast tumours, but less is known about the significance of IL8 in hormone-dependent breast cancer. The aim of this study was to evaluate the prognostic significance of IL8 and clinicopathological parameters in hormone-dependent breast cancer, and to examine possible associations between them that might imply possible biological dependence. The study included 91 early-stage breast cancer patients with detectable levels of hormone receptors (ER>0, PR>0). None of the patients received adjuvant therapy according to valid protocol at that time. HER2 status was determined on paraffin-embedded tumour tissue sections by CISH. IL8 levels were determined by ELISA in cytosol tumour extracts of 65 patients with long-term follow-up (144 months). Nonparametric statistical tests were used for data analyses. Patients with low IL8 levels (M<88.8 pg/mg) had significantly longer relapse-free survival (RFS) compared to patients with high IL8 levels (M≥88.82 pg/mg) (Log rank test, p=0.002). Patients with ERhighIL8low phenotype had significantly longer RFS compared to those with ERhighIL8high and ERlowIL8high phenotypes (p=0.04 and p=0.02, respectively); patients with PRlowIL8low phenotype had significantly longer RFS compared to those with PRlowIL8high and PRhighIL8high phenotypes (p=0.003 and p=0.02, respectively); patients with HER2-IL8low phenotype had significantly longer RFS compared to those with HER2-IL8high and HER2+IL8high phenotypes (p=0.01 and p=0.02, respectively). Our results indicate significant contribution of IL8 on survival of hormone-dependent early-stage breast cancer patients and association with established parameters such as ER/PR and HER2.