Detection of Gene Dosage in Circulating Free Plasma DNA as Biomarker for Lung Cancer

The increase in the number of gene copies at specific loci is a genetic alteration frequently associated with over expression of the related protein in cancer cells. Genes whose dose is consistently augmented in cancer include those involved in cell cycle control, proliferation, apoptosis, and angiogenesis among others. In this study, gene dose of onc ogenes MYCL1, MYCN, MYC, EGFR, ERBB2 and AKT2 in DNA obtained from lung tissue and blood plasma, of patients with primary lung cancer was evaluated with respect to normal lung tissue and plasma DNA of healthy individ uals, to determine the capacity of these genes to discriminate normal and neoplastic phenotypes. The number of copies of each gene was determined using real-time (2-△△CT). The AKT2 oncogene was found to be amplified frequently in plasma DNA from patients (74% of cases). This marker showed a noticeable ability to discriminate normal and neo-plastic phenotypes, with a 76 to 89% probability of correctly recognize a plasma sample provided by a lung cancer patient or a healthy individual. For this reason, this detection could be a very useful tool to supplement the existing diagnostic methods in pulmonary cancer.