Introduction
Background
Lung cancer is a malignant lung tumor characterized by uncontrolled cell growth in lung tissues. This growth can spread beyond the lung by the process of metastasis into nearby tissue or other parts of the body which can eventually cause death. The incidence rate of lung cancer is higher than any other common cancers in China. Among the ten most common cancers for men contemporarily, lung cancer stays the highest incidence rates, with approximately 1 out of 2000 males suffering from lung cancer each year.
Figure 1. Trends in Incidence Rates (Age-Standardized to the Segi Standard Population) for Selected Cancers for Males: China, 2000 to 2011.
ctDNA Detection
There are multiple lung cancer detection methods, and the most reliable and effective method is tissue biopsy. However, lung biopsy can cause serious complications such as Pneumothorax and bleeding. Therefore, liquid biopsy was introduced to minimized trauma and pain. Liquid biopsy, as the name implies, is the process of detecting the patients’ blood to determine the possibility of cancer. Unlike traditional biopsy, liquid biopsy does not require samples from patients' tumor but simply draw circulating blood samples. The common methods today for liquid biopsy are to detect circulating tumor DNA (ctDNA), circulating tumor cells (CTC) and secretion.
ctDNA, which stands for circulating tumor DNA, is tumor-derived fragmented DNA in the bloodstream that is not associated with cells. It is released by the dying cells during the biological process of apotheosis, necrosis, or active release from viable tumor cells.
ctDNA, which stands for circulating tumor DNA, is tumor-derived fragmented DNA in the bloodstream that is not associated with cells. It is released by the dying cells during the biological process of apotheosis and necrosis, or active release from viable tumor cells.
Figure 2. Circulating tumor DNA (ctDNA) is released by tumor cells and enters the circulation system.
Although the liquid biopsy avoid complication, common liquid biopsy required laboratory apparatus such as PCR instrument during the detection of ctDNA. So we want to take this method further, to develop a new liquid biopsy method of detecting ctDNA with a much simpler process.
