Expression of molecular factors correlated with metastasis in small cell lung cancer and their significance

Distant metastasis continues to be a fatal threat to quality of life in patients with small cell lung caner (SCLC). The purpose of this work is to analyze the expressions of chemokine receptor four (CXCR4), matrix metalloproteinase-9 (MMP-9), transforming growth factor-b1 (TGF-β1), N-cadherin and vascular endothelial growth factor (VEGF) in small cell lung caner (SCLC), and to explore their correlations with the prognosis and metastasis. Sixty-five consecutive patients with stage I-III SCLC who received operation in our hospital from Jan 2003 to Oct 2009 were retrospectively analyzed. The expression of CXCR4 was found significantly correlated with bone metastasis (P = 0.004), and were marginally correlated with brain metastasis (P = 0.068) and lymph node metastasis (P = 0.085). The expression of MMP-9 was significantly associated with pathological staging (P = 0.048). Univariate analysis suggested surgical approach, clinical stage, lymph node metastasis were significantly associated with OS and PFS (P < 0.05), high expression of CXCR4 was significantly correlated with worse OS (P = 0.004) and PFS (P = 0.005). Multivariate analysis suggested surgical approach, TGF-β1, CXCR4 and lymph node metastasis were independent prognostic factor for PFS. In conclusion, High expression of CXCR4, MMP-9, TGF-β1 and VEGF were found in SCLC. High expression of MMP-9 was significantly associated with pathological staging, and high expression of CXCR4 was correlated with bone metastasis and also might correlate with brain metastasis. CXCR4 were independent prognostic factor for survival in SCLC and expanded samples should be further explored in the future.