Detection of circulating antibodies to linear peptide antigens derived from ANXA1 and DDX53 in lung cancer

The EarlyCDT®-Lung test was the first autoantibody-based diagnostic tool for lungcancer, which was developed with a panel of recombinant protein antigens. Toconfirm whether the antibody test developed with linear peptide antigens has asimilar power to that developed with the whole protein molecules, the presentwork was then undertaken to develop an in-house enzyme-linked immunosorbent assaywith linear peptide antigens derived from annexin A1 (ANXA1) and DEAD box protein53 (DDX53), which have been used to develop the EarlyCDT®-Lung test. A total of272 patients with non-small cell lung cancer (NSCLC) and 227 control subjectsmatched in age and smoking history were recruited. Student's t test showed thatthe levels of circulating IgG to ANXA1-derived peptide antigens weresignificantly higher in patients with NSCLC than control subjects (t = 5.66,P < 0.0001), in which the increased anti-ANXA1 IgG levels were observed only inpatients at stages I, II, or III, but not in those at stage IV. However, thelevels of circulating IgG to DDX53-derived peptide antigens were notsignificantly altered in NSCLC (t = 1.78, P = 0.076). Receiver operatingcharacteristic analysis showed that the sensitivity against specificity of >90%was 23.7% for ANXA1 IgG assay and 13.8% for DDX53 IgG assay. This work suggeststhat the linear peptide antigen derived from ANXA1 may be suitable for thedevelopment of diagnostic tool for lung cancer although further screening isneeded to identify more such peptide antigens derived from tumor-associatedantigens.