Cancer Genetics and Epigenetics 2024, Vol.12, No.6, 317-328 http://medscipublisher.com/index.php/cge 320 3.2 Polymerase chain reaction (PCR)-based methods Polymerase Chain Reaction (PCR) remains a cornerstone in the detection of genetic mutations due to its simplicity, speed, and cost-effectiveness. PCR-based methods are widely used in clinical diagnostics to detect specific mutations in CRC, particularly in genes like KRAS, BRAF, and TP53. Techniques such as digital droplet PCR (ddPCR) and real-time PCR (qPCR) allow for the quantification of mutation burden and the detection of rare mutations with high sensitivity (Liebs et al., 2019). PCR-based methods are also essential in monitoring minimal residual disease and assessing treatment response. 3.3 Comparative genomic hybridization (CGH) Comparative Genomic Hybridization (CGH) is a technique used to detect copy number variations (CNVs) across the genome. CGH involves comparing the DNA of tumor cells to normal cells, allowing for the identification of genomic amplifications and deletions that may drive CRC progression. This method is particularly useful for identifying chromosomal instability, a hallmark of many colorectal cancers (Gao et al., 2019). CGH has been instrumental in uncovering novel genetic alterations that may serve as therapeutic targets or prognostic markers in CRC. 3.4 Liquid biopsy techniques Liquid biopsy techniques involve the analysis of circulating tumor DNA (ctDNA) in the blood, offering a non-invasive method to detect and monitor genetic mutations in CRC. Liquid biopsies are increasingly used for early detection, monitoring treatment response, and detecting recurrence. Techniques such as NGS and ddPCR are commonly applied to analyze ctDNA, allowing for the detection of mutations in genes like KRAS, BRAF, and PIK3CA with high sensitivity (Suzuki et al., 2020). Liquid biopsies are particularly valuable in cases where tissue biopsies are challenging to obtain or when continuous monitoring of tumor evolution is required (Reece et al., 2019). 3.5 Case study: application of NGS in a clinical setting A recent study demonstrated the application of NGS in a clinical setting for CRC patients. The study employed targeted NGS to analyze tumor and plasma samples, identifying mutations in key CRC-related genes such as APC, KRAS, and TP53. The use of NGS allowed for comprehensive mutation profiling, enabling personalized treatment plans based on the genetic landscape of each tumor. This approach not only improved diagnostic accuracy but also facilitated the monitoring of treatment efficacy and the early detection of recurrence (Osumi et al., 2018). 4 Clinical Relevance of Genetic Mutation Profiles Genetic mutation profiles in colorectal cancer (CRC) provide critical insights that inform diagnostic strategies, prognostic assessments, and therapeutic interventions. Understanding the clinical relevance of these mutations can significantly impact patient outcomes. 4.1 Diagnostic implications The identification of specific genetic mutations in CRC plays a crucial role in enhancing diagnostic accuracy and enabling early intervention. 4.1.1 Early detection Genetic mutations such as those in the APC, KRAS, and TP53 genes are often present in early-stage colorectal tumors and can be detected through advanced techniques like Next-Generation Sequencing (NGS). Early detection of these mutations allows for timely intervention, improving the chances of successful treatment outcomes (Kim et al., 2019; Ye et al., 2020). 4.1.2 Differentiating between subtypes of CRC Genetic profiling enables the differentiation between various subtypes of colorectal cancer, which is essential for accurate diagnosis and personalized treatment planning. For instance, BRAF mutations are more frequently associated with right-sided CRCs, which have distinct clinical features and treatment responses compared to
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