Circulating free DNA (cfDNA) is genetic material released from various cells into bodily fluids. Among its fractions, circulating tumor DNA (ctDNA) originates from tumor cells and reflects their genetic material, including mutations and epigenetic changes. Methods commonly employed for detecting ctDNA in blood include next-generation sequencing (NGS) and various types of PCR. The presence of ctDNA can be utilized in liquid biopsies for many diagnostic purposes related to various cancers. It is a minimally invasive method of sampling molecular compounds from tumor cells. In this paper, we focus on current knowledge regarding the liquid biopsy of blood ctDNA in the context of lung cancer, one of the leading causes of cancer-related mortality. Currently, as a clinically approved method, liquid biopsy serves as a complementary technique in NSCLC diagnostic and genetic profiling. Other applications of liquid biopsy that are still being investigated include the detection of minimal residual disease (MRD) after curative treatment and response monitoring to systemic treatment. This review discusses current and future potential directions for the development and implementation of ctDNA for patients with NSCLC.

Background: The current treatment of gastroesophageal reflux disease (GERD) is focused on decreasing gastric acid secretion. However, there is still a group of patients that do not respond to conventional therapy. Proteinase-activated receptors and purinergic receptors have been implicated in inflammation, visceral hyperalgesia and esophageal hypersensitivity. The aim of this study was to evaluate the esophageal expression of PAR2 (F2RL1) and P2RX2, P2RX3 and P2RY2 in GERD patients. Methods: A total of 53 patients with GERD and 9 healthy controls were enrolled in this study. The expression of the studied receptors was quantified using real-time PCR on esophageal biopsies from the patients with GERD and healthy controls. The correlation between the dilated intracellular spaces (DIS) score and patients’ quality of life was investigated. Results: PAR2 receptor expression was higher in ERD compared to NERD and controls (326.10 ± 112.30 vs. 266.90 ± 84.76 vs. 77.60 ± 28.50; NS). P2X2 exhibited the highest expression in NERD compared to ERD and controls (302.20 ± 82.94 vs. 40.18 ± 17.78 vs. 26.81 ± 10.27), similarly to P2Y2, which expression was higher in NERD than in ERD and controls (7321.00 ± 1651.00 vs. 5306.0 ± 1738.00 vs. 3476.00 ± 508.0). Conclusions: We found that the expression of F2RL1, P2RX2 and P2RY2 is positively correlated to the DIS score in GERD patients. Higher PAR2, P2X2 and P2Y2 expression could mediate the sensitization of the esophagus and may be associated with the higher intensity of symptoms perceived by NERD patients.

Background: Current treatment of gastroesophageal reflux disease (GERD) is focused on decreasing the gastric acid secretion. However, there is still a group of patients not responding to conventional therapy. Proteinase-activated receptors and purinergic receptors have been involved in inflammation, visceral hyperalgesia, and esophageal hypersensitivity. The aim of this study was to evaluate the esophageal expression of PAR2 (F2RL1) and P2RX2, P2RX3 and P2RY2 in GERD patients. Methods: The expression of studied receptors was quantified using real-time PCR in esophageal biopsies in patients with GERD and healthy controls. Correlation between dilated intracellular spaces (DIS) score and patients’ quality of life was investigated. Results: PAR2 receptor expression was higher in ERD compared to NERD and controls (326.10±112.30 vs 266.90±84.76 vs 77.60±28.50; NS).P2X2 exhibited the highest expression in NERD compared to ERD and controls (302.20±82.94 vs 40.18±17.78 vs 26.81±10.27), similarly to P2Y2 which expression was higher in NERD than in ERD and controls (7321.00±1651.00 vs 5306.0±1738.00 vs 3476.00±508.0). Conclusions: We found that the expression of F2RL1, P2RX2 and P2RY2 is positively correlated to DIS score in GERD patients. Higher PAR2, P2X2 and P2Y2 expression could mediate sensitization of esophagus and may be associated with higher intensity of symptoms perceived by NERD patients.