From genomic instability to epigenetic regulation: the role of DNA repair gene variants and non-coding RNAs in colorectal carcinogenesis.

Colorectal cancer (CRC) pathogenesis is a multi-step process characterized by a transition from genomic instability to complex epigenetic regulation, wherein DNA repair gene variants and non-coding RNAs (ncRNAs) play a critical role in carcinogenesis. By synthesizing data on chromosomal instability (CIN), signal transduction dysregulation, and the "sponge" effect of lncRNAs, this review highlights how these polymorphic and epigenetic landscapes dictate disease susceptibility and therapeutic response. Through the examination of major DNA repair pathways-including Mismatch Repair (MMR), Base Excision Repair (BER), Nucleotide Excision Repair (NER), and Double-Strand Break Repair (DSBR)-it is evident that variants in genes such as MLH1, MUTYH, ERCC1, and BRCA1 compromise genomic stability, while polymorphisms in key signaling axes like Wnt/β-catenin, MAPK/ERK, PI3K/AKT, and apoptotic regulators such as Bax, Bcl-2, and TP53 significantly contribute to the adenoma-to-carcinoma transition and chemotherapy resistance. Furthermore, emerging evidence underscores the dual role of microRNAs (miRNAs) and long non-coding RNAs (lncRNAs) as both potent epigenetic regulators and promising noninvasive biomarkers, although challenges regarding clinical standardization and ethnic variability persist. Ultimately, a comprehensive understanding of these genetic markers is essential for transitioning toward personalized oncology, as integrating multi-omic polymorphic data into clinical practice will enhance early detection strategies and facilitate the development of targeted therapeutic interventions tailored to the patient's unique genetic profile.