Cell-free DNA in chemical carcinogen induced mouse lung cancer and colon cancer model: its implications in diagnostics and therapeutics.

Chemical carcinogen induced mouse models closely mimic environmentally driven human cancers and provide platforms for studying tumor initiation and progression. However, the behavior and diagnostic value of cell-free DNA (cfDNA) in such models remain poorly understood, limiting their translational utility for biomarker development. Considering the increasing clinical relevance of cfDNA for early detection and treatment monitoring, this study aimed to systematically characterize cfDNA dynamics and genomic alterations in B(a)P induced lung cancer and DMH induced colon cancer mouse models. The aim was to evaluate cfDNA as a minimally invasive biomarker that reflects tumor burden and its potential use in preclinical diagnostic and therapeutic studies. Mouse lung and colon cancers were induced using B(a)P and DMH, respectively. Plasma was collected at defined time points, cfDNA was isolated, quantified, and analyzed for integrity profiles. Real time assessment was performed using liquid biopsies of cell free DNA using NGS-WGS platform for non-invasive tumor detection in live animals, reserving histopathology for post-mortem analysis. Our results reveal circulating cell-free DNA mutations similar to those found in humans (Lung cancer: ALK, NRAS, NF1, BRAF, FGFR1OP, FGFR1, STK11ip, AKT1 & AK1S1; Colon cancer: APC, MYC, KRAS). We have performed gene enrichment and protein-protein interactions and found various cancer related genes. The histopathological examination revealed neoplastic changes that corroborated with genomic studies. This study establishes cfDNA as a potential surrogate biomarker in chemical carcinogen induced lung and colon cancer models, supporting its utility for early detection, disease monitoring, and preclinical therapeutic assessment.