Circulating poly(ADP-ribose) levels in lung cancer: an exploratory study

Poly(ADP-ribose) (PAR) is a polymer generated during poly(ADP-ribosyl)ation, a post-translational modification involved in cellular stress responses and DNA repair. Although PAR-related pathways have been investigated in cancer biology, the clinical significance of circulating PAR levels in patients with lung cancer remains insufficiently characterized. With this study, we investigate the serum levels of PAR in patients with lung cancer and compare them with healthy individuals to assess its potential role as a prognostic biomarker. Serum samples from 23 patients with primary lung cancer who had not received prior cancer treatment and 21 healthy controls were analyzed using a commercial ELISA-based assay. Group differences were evaluated, including an analysis adjusted for age. Our findings demonstrated that the mean serum PAR levels in lung cancer patients were approximately twofold higher compared to the control group (p<0.05). The elevated PAR levels observed in lung cancer patients suggest an upregulation of poly ADP-ribosylation activity, possibly as a response to increased genomic instability and cellular stress associated with tumor progression. This finding supports the hypothesis that PAR metabolism is actively involved in lung carcinogenesis and may serve as a valuable biomarker in evaluating disease prognosis. Our results indicate that PAR levels are significantly elevated in the serum of lung cancer patients compared to healthy individuals. However, the results do not establish the diagnostic accuracy, prognostic value, treatment-predictive capacity, or clinical utility of circulating PAR. Larger, well-characterized prospective studies incorporating clinical and molecular data and serial measurements are needed to validate this observation.