The prognostic significance of serum interferon-gamma (IFN-γ) in hormonally dependent breast cancer

Background: Interferon-gamma (IFN-gamma) is a pleiotropic immunomodulatory cytokine. Because of its contradictory and even dualistic roles in malignancies, its potential as a biomarker remains to be unraveled. Aim: To evaluate the prognostic significance of serum IFN-gamma in hormonally treated breast cancer patients. Material and methods: The study included 72 premenopausal breast cancer patients with known clinicopathological characteristics. All patients received adjuvant hormonal therapy based on hormone receptor-positivity. The median follow-up period was 93 months. IFN-gamma serum protein levels were determined by quantitative ELISA. Prognostic performance was evaluated by the receiver operating characteristic (ROC), Cox proportional hazards regression and Kaplan-Meier analyses. Classification of patients into IFN-gamma(low) and IFN-gamma(high) subgroups was performed by the use of the outcome-oriented cut-off point categorization approach. Results: The best prognostic performance was achieved by IFN-gamma (AUC = 0.24 and p = 0.01 for distant events, AUC = 0.29 and p = 0.01 for local and distant events combined). Age and IFN-gamma were prognostically significant in instances of all types of outcomes and IFN-gamma was the independent prognostic parameter (Cox regression). There was a significant difference between IFN-gamma values of patients without any events and those with distant metastases (Mann-Whitney test, p = 0.007). IFN-gamma levels correlated significantly with nodal status and tumor stage (Spearman's rank order, r =-0.283 and r = -0.238, respectively). Distant recurrence incidence was 4% for the IFN-gamma(high) subgroup and 33% for the IFN-gamma(low) subgroup (Kaplan-Meier analysis). Conclusions: Raised serum IFN-gamma levels associate independently with favorable disease outcome in hormonally dependent breast cancer.

Automated summary

This study evaluated the prognostic significance of serum IFN-gamma in hormonally treated breast cancer patients and found that raised IFN-gamma levels were independently associated with favorable disease outcome in hormonally dependent breast cancer.