ADAM28 is a serological and histochemical marker for non-small-cell lung cancers

ADAM28 (a disintegrin and metalloproteinase 28) is over-expressed in non-small-cell lung cancer (NSCLC) with correlation to cancer cell proliferation, tumor size and lymph node metastasis. The present study was aimed to develop an enzyme-linked immunosorbent assay (ELISA) system for diagnosis and monitoring of NSCLC. Our ELISA specifically measured ADAM28, showing negligible cross-reactivity with other metalloproteinases. The ADAM28 level in the NSCLC tissue was remarkably 36.9-fold higher than that in the non-neoplastic lung tissue (p < 0.001). The serum level was significantly 4.6-fold higher in the NSCLC patients (5.41 +/- 8.62 ng/ml; n = 102) than in the control subjects (1.17 +/- 0.93 ng/ml; n = 20) (p < 0.001), and increased with progress of tumor stage (p < 0.001). The level was also significantly higher in the patients with recurrent carcinoma than the control (p < 0.001) and in the patients with lymph node metastasis than those without metastasis (p < 0.001). The sensitivity, false-negative rate and AUC for ADAM28 were better than those for carcinoembryonic antigen. The combination of both assays improved the sensitivity, specificity, false-positive and false-negative rates for NSCLC. There was a positive correlation between the ADAM28 level measured by ELISA system and the degree of immunostaining in the lung adenocarcinomas with a size of <= 20 mm in diameter. The adenocarcinoma patients showing the high immunohistochemical reaction exhibited a poorer disease-free survival than those with the lower immunoreactivity (n = 102; p < 0.05). These data demonstrate that our ELISA is specific and sensitive to monitor the levels of ADAM28 in the samples from NSCLC patients and suggest that ADAM28 is a useful serological and histochemical marker for NSCLC.