Systemic Inflammatory Response as a Prognostic Factor in Breast Cancer. Part I. Tumor-Promoting Inflammation. Serum Inflammatory Markers

Chronic inflammation caused by exposure to external or internal factors increases the risk of developing malignancies and promotes tumor progression due to the influence on the key elements of carcinogenic mechanisms. At the system level signs of a chronic inflammation are manifested by an increase of inflammatory mediators and acute phase proteins levels in the blood, a change in the ratio of circulating leukocyte populations, and disturbances in the hemostasis system. This review is devoted to serum and hematological parameters of the systemic inflammatory response (SIR) in breast cancer (BC). The first part of the review outlines general concept about the role of inflammatory factors in the development of malignant tumors. It provides information on the most well studied serum inflammatory markers in breast cancer: cytokines, including interleukin-6 (IL-6), interleukin-8 (IL-8), tumor necrosis factor-alpha (TNF-), as well as C-reactive protein (CRP). The main properties of these polypeptides, which link them with tumor-promoting inflammation, are considered. An analysis of the data on the clinical significance of the serum level of cytokines and CRP in breast cancer accumulated to date is presented. Correlations of the elevated levels of the serum inflammatory markers with clinical and morphological characteristics of the disease, tumor response to chemotherapy, overall and relapse-free survival of patients indicate the feasibility of in-depth investigation of the issue for the purpose of the practical application of the systemic inflammatory markers as predictive and prognostic indicators in BC.