The relationship between breast cancer (BC) and inflammation remains unclear.Several well-established risk factors for BC, such as advancing age, obesity and late age of first pregnancy, are associated with increased levels of circulating proinflammatory cytokines and systemic inflammation.Tumor-associated macrophages may comprise 50% of the breast tumor mass and the extent of infiltration is associated with increased angiogenesis and poor prognosis.T-lymphocyte infiltration into invasive breast carcinoma is associated with extensive and higher-grade ductal carcinoma in situ and invasive carcinoma.Acute activation of B cells has an anticancer role; controversially, some studies suggest that B-lymphocytic infiltration may play a role in tumor progression.Myleoid-derived suppressor cells may contribute to tumor-induced bone disease.
The prognostic value of breast tumor infiltration with mature dendritic cells in BC is limited.Increased levels of IL-6, IL-1b and TNF-a are associated with poorer prognosis.CLL5 and CLL2 chemokines are associated with advanced tumor growth and metastases.Major anti-inflammatory cytokines, such as IL-4, IL-10, IL-13, IL-35 and COX-2, have been found to be associated with aggressive BC, including larger tumor size and higher grade.A meta-analysis of 38 studies showed that the use of nonsteroidal anti-inflammatory drugs leads to a reduced risk of BC.NF-kB activity has been associated with estrogen receptor-negative tumors and a more aggressive phenotype in estrogen receptor-positive tumors.