Circulating Inflammatory and Mitochondrial Biomarkers Associated with Cachexia in Advanced Non-Small Cell Lung Cancer

<b>Background</b>: Cancer-associated cachexia is a multifactorial metabolic syndrome characterized by progressive skeletal muscle and/or adipose tissue loss and affects approximately 40% of patients with non-small cell lung cancer (NSCLC). However, reliable circulating biomarkers for early detection and risk stratification remain undefined. Based on prior observations linking elevated circulating mitochondrial DNA (mtDNA) to cachexia, we hypothesized that mtDNA and inflammatory protein levels in plasma could predict cachexia onset and trajectories. <b>Methods</b>: We evaluated 27 patients with stage IV NSCLC enrolled in the SeroNet-CORALE cohort with plasma samples collected between 2020 and 2023. Forty biomarkers were quantified at two timepoints (T1 and T2) using a multiplexed MesoScale Discovery platform. Associations between log2-transformed biomarker levels and cachexia status were assessed using Firth's penalized logistic regression. <b>Results</b>: Among 27 patients (65% female; mean age 65 ± 10 years; 89% adenocarcinoma histology), cachectic patients exhibited lower body mass index at both time points (T1: 21.0 ± 2.0 vs. 27.0 ± 7.0; T2: 21.8 ± 4.9 vs. 25.2 ± 4.9). At T1, cachexia was strongly associated with elevated GDF15 (OR 4.29; 95% CI 1.04-29.74; <i>p</i> = 0.044) and IL-15 (OR 43.83; 95% CI 2.39->999; <i>p</i> = 0.007), whereas IL-4 had a protective association (OR 0.09; 95% CI 0.00-0.66; <i>p</i> = 0.013). At T2, cachexia was associated with higher mtDNA levels (OR 2.13; 95% CI 1.07-7.69; <i>p</i> = 0.022) and lower levels of IL-15, IL12/IL23p40, and MDC. <b>Conclusions</b>: Distinct inflammatory and mitochondrial biomarkers tracked cachexia evolution in advanced NSCLC, with early GDF-15/IL-15 elevations and later increases in circulating mtDNA. Larger longitudinal studies are warranted to validate these findings and define their clinical relevance.