Correlation effect of EGFR and CXCR4 and CCR7 chemokine receptors in predicting breast cancer metastasis and prognosis

Abstract

Background: The chemokine receptors CXCR4 and CCR7 play an important role in cancer invasion and metastasis. This study investigated the expression of CXCR4, CCR7, CXCL12, CCL21, and EGFR to illustrate the role of these biomarkers in breast cancer metastasis and prognosis.

Methods: The CXCR4, CCR7, CXCL12, CCL21, and EGFR biomarkers were analyzed along with ER, PR, and HER-2/neu in breast cancer tissue microarray (TMA) specimens, including 200 primary breast cancer specimens by immunohistochemistry. Corresponding lymph nodes from the same patients were also examined using the same method.

Results: Together with their CXCL12 and CCL21 ligands, CXCR4 and CCR7 were significantly highly expressed in tumor cells with lymph node (LN) metastasis. Similarly, EGFR was expressed highly in tumors with LN metastasis. The ligands were especially expressed in metastatic tumors than in primary tumors from the same patients. Moreover, the expression of both CXCR4 accompanied by CCR7 and CXCL12 accompanied by CCL21 were up-regulated. Kaplan-Meier survival analysis revealed that patients exhibiting high CXCR4, CCR7, and EGFR expression experienced a shorter survival period compared with those with low expression.

Conclusions: The expression of CXCR4, CCR7, and EGFR may be associated with LN metastasis. Moreover, the expression of these receptors can serve as an indicator of undesirable prognosis in patients with breast cancer.

Figure 1

IHC staining for biomarkers. IHC staining for CXCR4, CXCL12, CCR7, CCL21 and EGFR. PT pertains to primary tumor, while LNMT stands for lymph node metastasis tumor. Rows correspond to the designated chemokine or receptor. The first column represents staining of negative expression in primary breast cancer with the indicated antibody. The second column indicates positive expression in primary breast cancer, and the third column shows positive expression in lymph node metastasis cancer. Both PT and LNMT columns in each row are obtained from the same patient while the negative column is not. In the CXCR4 row, A2 and A3 exhibit high expression in both cytoplasm and nucleus. CCR7, CXCL12, and CCL21 all exhibit positive reaction in the cytoplasm. In the EGFR row, E2 and E3 indicate that EGFR is expressed mainly in the membrane. However, a number of tumor cells appear to be positive in the cytoplasm as well (Panels A-E, ×200).

Figure 2

Overall survival analysis for CXCR4 cytoplasmic expression. Kaplan-Meier curves for overall survival (OS) in 110 patients with high expression of CXCR4 and 90 patients with low expression of CXCR4 in cytoplasm. Survival time sharply decreased in patients with high CXCR4 cytoplasmic expression, especially in the first five years, Meanwhile, survival of patients with low CXCR4 expression was merely moderately affected (P = 0.011).

Figure 3

Overall survival analysis for CXCR4 nuclear expression. Kaplan-Meier curves for overall survival (OS) in 113 patients With high CXCR4 expression and 87 patients with low CXCR4 expression in the nucleus. Survival time sharply decreased in patients with high CXCR4 nuclear expression, especially in the first five years, when significantly compared with those exhibiting low expression (P = 0.003).

Figure 4

Overall survival analysis for CCR7 expression. Kaplan-Meier curves for overall survival (OS) in 111 patients with high CCR7 expression and 89 patients with low CCR7 expression in the cytoplasm. The difference between these two groups is not highly significant as determined by the log-rank test (P = 0.044). However, it can be observed from the curve that in the first five years, survival rate sharply decreased in patients with high CCR7 expression in the cytoplasm, while hardly any patient in the low expression group died during the first five years.

Figure 5

Overall survival analysis for EGFR expression. Kaplan-Meier curves for overall survival (OS) in 88 patient with high EGFR expression and 112 patients with low EGFR expression in the membrane and cytoplasm. Survival rate of patients with high EGFR expression was significantly low compared with those exhibiting low expression (P = 0.007).