P0151 Association of plasma CXCL12 and bone metastasis in advanced stage non-small-cell lung cancer

Abstract

<h3>Background</h3> CXCL12/CXCR4 has been shown to play critical roles in cancer metastasis. In non-small-cell lung cancer (NSCLC), a higher level of plasma CXCL12 has been demonstrated in patients with pleural metastasis. In addition, an altered CXCL12/CXCR4 pathway is involved in the bone metastatic process in other cancers. Here, we investigate a correlation between plasma CXCL12 and bone metastatic phenotype in NSCLC. <h3>Methods</h3> NSCLC patients who received treatment at the Medical Oncology Unit, King Chulalongkorn Memorial Hospital between May 2013 to Jan 2014 were enrolled. Key inclusion criteria included advanced stage NSCLC. Baseline plasma CXCL12 prior to any treatment were collected. Bone metastasis was diagnosed by bone scan, CT scan, PET or MRI imaging of involved skeletal parts. We used Anti-CXCL12 (R&D system, Minneapolis, MN) to detect CXCL12 in plasma. Correlations between CXCL12 levels to clinical parameters including presence of bone metastasis were analysed. <h3>Findings</h3> Fifty-five eligible NSCLC patients were enrolled. Among these were 24 patients with definite evidence of bone metastasis and 23 patients without detectable bone metastasis at baseline. There were eight patients who had inconclusive bone metastasis by imaging. Mean plasma CXCL12 in patients with bone metastasis was higher than for those without bone metastases (2174.79 ±526.26pg/mL versus 1951.06 ±820.43pg/mL (<i>p</i>=0.26). There was a trend of increasing plasma CXCL12 levels correlated with number of organs with metastases: 2165.10 ±667.48pg/mL, 2097.43 ±685.65pg/mL, and 1942.050 ±636.38pg/mL in patients with three or more, two, and none to one organ with metastasis, respectively. In addition, patients with bone-only metastasis, combined metastases, and no bone metastasis had an increasing trend of plasma CXCL12: 2339.00 ±287.43pg/mL, 2120.05 ±581.13pg/mL, and 1856.59 ±772.50pg/mL, respectively (<i>p</i>=0.20). <h3>Interpretation</h3> Our results demonstrate a correlation between plasma CXCL12 and bone metastasis in NSCLC patients. Further study in a larger population is warranted to confirm the potential of CXCL12 as a useful biomarker of bone metastasis in lung cancer.