Despite advances in treatments,
lung cancer has been the leading cause of
cancer-related deaths in the United States for the past several decades. Recent findings from the National Lung Screening Trial reveal that low-dose helical computed tomography (CT) scan screening of high-risk individuals reduces
lung cancer mortality. This suggests that early detection is of key importance to improving patient outcome. However, of those screened with CT scans, 25% had positive scans that require further follow-up studies which often involve more radiation exposure and invasive tests to reduce false positive results. The purpose of this study was to identify candidate plasma
biomarkers to aid in diagnosis of
lung cancer in at-risk individuals. We found increased expression of the
CXC chemokine connective tissue-activating peptide (
CTAP)-III from plasma specimens of
lung cancer patients compared to at-risk control subjects. Identification of the
peptide was confirmed by the addition of an anti-NAP-2 antibody that recognizes
CTAP-III and NAP-2. We also quantified and verified the increased levels of plasma
CTAP-III with ELISA in patients with
lung cancer (mean ± SD, 1859 ± 1219 ng/mL) compared to controls (698 ± 434 ng/mL; P<0.001). Our findings demonstrate elevated plasma levels of
CTAP-III occur in
lung cancer patients. Further studies are required to determine if this
chemokine could be utilized in a blood-based
biomarker panel for the diagnosis of
lung cancer.