Significance of expression of stromal cell derived factor 1 and CXCR4 in invasive breast cancer

Abstract

To study the expression of stromal cell derived factor 1(SDF-1)/CXCR4 and their association with clinicopathologic features and lymph node metastasis in invasive breast carcinoma. The expression of SDF-1 was studied by immunohistochemistry and in-situ hybridization. Immunohistochemical study for CXCR4 was also performed. The correlation with various clinicopathologic parameters was analyzed. (1) SDF-1 was mainly expressed in tumor cells and the level of its expression (both membranous and cytoplasmic) in lymph node-positive group was higher than that in lymph node-negative group (P = 0.033). Only cytoplasmic expression correlated with the number of positive lymph node involved by metastasis, TNM tumor stage, histologic grade, tumor dimension and estrogen receptor status (P < 0.05). (2) SDF-1 protein was also detected in the endothelial cells, although its mRNA was rarely detected. SDF-1 staining in lymphatics was associated with positive lymph node (P = 0.005) and SDF-1 staining in blood vessels correlated with stromal lymphocytic reaction (P = 0.001). The extent of nodal involvement was higher in the group with positive SDF-1 staining in blood vessels and with prominent lymphocytic reaction than that in other groups with one or neither of the two features (P < 0.05). (3) On the other hand, CXCR4 was mainly expressed in tumor cells (both nuclear and cytoplasmic); and the level of its expression in lymph node-positive group was higher than that in lymph node-negative group (P = 0.005). Only cytoplasmic expression correlated with the number of positive lymph node involved by metastasis, TNM tumor stage, histologic grade, tumor dimension and HER2 status (P < 0.05). The nuclear expression of CXCR4 was only correlated with progesterone receptor status (P < 0.01). The cytoplasmic expression CXCR4 also positively correlated with SDF-1 expression (P = 0.001). SDF-1 and CXCR4 can serve as biomarkers for diagnosis and prediction of lymph node metastasis, as well as potential therapeutic targets in invasive breast carcinoma. The difference in localization and staining patterns may also carry different significance.