Study of circulating IgG antibodies to BIRC5 and MYC in non‐small cell lung cancer

Abstract

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'st‐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 combinedP‐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 combinedP‐value of 0.00003 (X2= 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.

Keywords

• Lung cancer
• BIRC5
• MYC
• Autoantibodies
• ELISA
• Tumor immunity