Description: Publication date: Available online 25 September 2015 Source: FEBS Open Bio Author(s): Leiguang Ye, Weili Wang, Cairen Chen, Qingyong Meng, Yan Yu An in-house enzyme-linked immunosorbent assay (ELISA) was developed in this study to detect circulating IgG antibodies to peptide antigens derived from baculoviral IAP repeat-containing protein 5 isoform 2 (BIRC5) and myc proto-oncogene protein (MYC) in non-small cell lung cancer (NSCLC). Student’s t -test revealed that circulating anti-MYC IgG levels were significantly increased in patients with NSCLC compared with control subjects in the discovery sample ( t =3.96, P =0.0001) but not in the validation sample ( t =1.24, P =0.217), generating a combined P -value of 0.0003. Neither the discovery sample nor the validation sample showed a significant change in anti-BIRC5 IgG levels in NSCLC. Further analysis was performed to investigate whether circulating IgG antibodies to these two tumor-associated antigens (TAAs) significantly changed with early (stages I+II) and late (stages III+IV) NSCLC stages. The results showed that neither anti-MYC IgG nor anti-BIRC5 IgG levels significantly changed in patients with early stage NSCLC, while patients with late stage NSCLC had higher levels of circulating anti-MYC IgG than control subjects in the discovery sample ( t =4.74, P 〈0.0001) but not in the validation sample ( t =0.80, P =0.423), generating a combined P -value of 0.00003 ( X 2 =26.13, df =4). In conclusion, circulating IgG antibodies to MYC and BIRC5 do not appear to serve as biomarkers for early diagnosis of lung cancer but anti-MYC IgG might have a prognostic value