Objective: To explore the expressions of CXC chemokine receptor 4 (CXCR4) and matrix metalloproteinase-9 (MMP-9) and examine their correlations with metastasis and prognosis in small cell lung cancer (SCLC).
Methods: Immunohistochemistry was employed to detect the expressions of CXCR4 and MMP-9 in the tissue samples from 65 SCLC patients treated in Cancer Institute and Hospital Attached to Tianjin Medical University from January 2003 to October 2009. And their correlations with metastasis and prognosis were analyzed by Chi-square test and Kaplan-Meier method and Cox regression.
Results: The positive expression rates of CXCR4 and MMP-9 were 100.0% (65/65) and 87.7% (57/65) in SCLC tissues respectively. Significant difference of the expression rate of CXCR4 was found between patients undergoing bone metastasis or not (P = 0.004). But the differences were not significant between brain metastasis or not (P = 0.068) and lymph node metastasis or not (P = 0.085). A high expression rate of MMP-9 was significantly associated with pathological staging (P = 0.048). But the difference between lymph node metastasis or not was not significant (P = 0.085). Univariate analysis suggested that a high expression rate of CXCR4 was significantly correlated with the disease-free survival (DFS) of SCLC patients (P = 0.005). But a high expression rate of MMP-9 was not associated with DFS (P = 0.341). Multivariate analysis suggested that a high expression rate of CXCR4 was an independent prognostic factor for DFS in SCLC.
Conclusions: The elevated levels of CXCR4 and MMP-9 are found in SCLC tissues. And the expression rate of CXCR4 may be correlated with bone metastasis, but the correlation is not notable for MMP-9. The expression rate of CXCR4 is an independent prognostic factor for DFS in SCLC.