CCR7 immune cell receptor expression in inflammatory breast cancer.

Inflammatory breast cancer (IBC) is characterized by congestion of dermal lymphovascular spaces by tumor emboli. We characterized expression of CCR7, a lymphocyte homing chemokine receptor, in IBC cell lines and patient tissues. CCR7 gene expression was quantified using World IBC Consortium Database and correlated with protein expression in cell lines and IBC mastectomy samples post-neoadjuvant therapy. CCR7 expression on tissue microarray (TMA) was scored by staining pattern (complete vs. incomplete membranous), percent tumor stained, and staining intensity. CCR7 was highly expressed in IBC cell lines and a previously validated preclinical mouse model. Among 137 IBC and 252 non-IBC patient samples, CCR7 gene expression was significantly higher in IBC compared to non-IBC (p = 0.0007). Within IBC samples, gene expression was higher in HER2+ (p = 0.0002), basal (p = 0.0161), and ER- IBC patients (p = 0.010). Of the 24 IBC TMAs, almost all were CCR7 positive (23, 95.8%), with 15 (62.5%) demonstrating completely membranous expression. CCR7 is highly expressed in IBC cell lines and patient tumor samples, with preferential expression in HER2-positive and basal-like IBC subtypes. Given its high prevalence, CCR7 may serve as a potential target for antibody-based drug design in future IBC studies.