Aspartyl (asparaginyl) β-hydroxylase (AABH), a serum biomarker for lung cancer.

45 Background: There are no serum biomarkers currently approved for the detection of lung cancer, a leading cause of cancer associated mortality world wide. More than 180,000 cases of lung cancer will be diagnosed in the United States in 2020 by other means such as by X-ray and CT scanning methods, which have inherently lower sensitivity and higher cost when compared generally to serological methods. While the five year survival for lung cancer is 15%, a survival rate of 50% can be achieved when detection is made early in individuals with localized cancer. Current detection methods, however, enable such detection in only about 18% of cases overall. Methods: A prospective serum biomarker Aspartyl (Asparaginyl) ß Hydroxylase (AABH), has been previously found to be elevated by immunohistochemical staining (IHC) in a broad range of cancers, including lung cancer. AABH was detected in > 99% of tumor specimens tested (n > 1000) but absent in adjacent tissue. The present study introduces a double monoclonal sandwich ELISA which provides detection and comparative quantification of AABH in serum of lung cancer patients vs. normal, and high-risk controls such as cigarette smokers without cancer. This is relevant since 87% of lung cancers are attributable to cigarette smoking, and associative parallels can be seen with recent reductions in rates of smoking. Results: Increased levels of serum AABH were found in 99% of patients with lung cancer (n = 192). Serum AABH was found to be undetectable in individuals not known to have cancer (n = 129, specificity = 93%). In patients with lung cancer, AABH was detectable at all stages. In a population of 50 smokers not known to have cancer, the mean serum AABH level was 0 ng/ml with 90% specificity. Conclusions: The AABH serum ELISA therefore has great promise as an additional diagnostic tool for lung cancer having the practicality and cost effectiveness of conventional serological screening. Elevated serum AABH in conjunction with CT scanning may greatly facilitate earlier diagnosis of lung cancer at a stage in which cure rates are significantly higher and thus may contribute to increased patient survival.