ESR1 and breast cancer: Because Cytokines are secreted by the tumor microinveronment (TME), stimulating the transcription of LCN2 by inducing the activation and binding of transcription factors such as CCAAT/enhancer-binding protein (C/EBP) to the LCN2 promoter region [11], high levels of lipocalin 2 associated with the ER-negative, PR-negative subtype of breast cancer may also be explained by the fact that several studies have demonstrated an increase in inflammatory infiltrates in the subtype of hormone receptor-negative breast cancer [17].