Are circulating autoantibodies to ABCC3 transporter a potential biomarker for lung cancer?

PURPOSE: The present study was undertaken to test circulating autoantibody to ATP-binding cassette C3 (ABCC3) transporter in order to confirm whether anti-ABCC3 antibody could serve as a biomarker for early diagnosis of lung cancer. METHODS: This study recruited 275 patients (178 males and 97 females) with non-small cell lung cancer (either squamous carcinoma or adenocarcinoma) and 226 control subjects (134 males and 92 females) well matched in age and smoking history. Anti-ABCC3 IgA and IgG were determined using an enzyme-linked immunosorbent assay (ELISA) approach that was developed in house with the human leukocyte antigen class II (HLA-II) restricted antigens. RESULTS: Mann-Whitney U test showed that the IgG antibody level was significantly higher in female patients with adenocarcinoma than female controls (Z = -4.34, P < 0.001) and that the IgA antibody level was significantly higher in male patients with squamous carcinoma than male controls (Z = -3.12, P = 0.002). Pearson's Chi-square (χ(2)) test showed that female patients with adenocarcinoma had a significantly higher positive rate for IgG autoantibody than female controls (χ ( 2 ) = 8.73, P = 0.003). The ELISA sensitivity against a specificity of >95 % was 18.1 % for IgG assay in female patients and 18.0 % for IgA assay in male patients. The inter-assay deviation was 10.6 % for IgG assay and 14.5 % for IgA assay. CONCLUSIONS: Circulating autoantibodies to ABCC3 transporter may be a potential biomarker that can be added to a panel of existing biomarkers for early diagnosis and prognosis of lung cancer although the gender differences should be taken into account.