Cancer Genetics and Epigenetics 2024, Vol.12, No.5, 279-293 http://medscipublisher.com/index.php/cge 280 of breast cancer. It will thoroughly evaluate the developed genetic markers and diagnostic techniques, exploring their accuracy and practicality while analyzing the challenges encountered in real-world applications. Furthermore, the study will comprehensively review how genetic diagnostics can facilitate the early detection of breast cancer, thereby improving patient prognosis. This research will provide valuable insights and recommendations for the field of early breast cancer diagnosis. 2 Genetic Basis of Breast Cancer 2.1 The relationship between breast cancer and genetic susceptibility Breast cancer is a complex disease with a significant genetic component. Approximately 5-10% of breast cancer cases are considered hereditary, with a substantial portion attributed to mutations in specific genes (Economopoulou et al., 2015). Family history remains one of the strongest risk factors for breast cancer, as women with a first-degree relative affected by the disease are twice as likely to develop it themselves (Dalivandan et al., 2021). This hereditary risk is primarily due to shared genetic factors rather than shared environmental or lifestyle factors. Genetic susceptibility to breast cancer is influenced by both high-penetrance genes, such as BRCA1 and BRCA2, and moderate-penetrance genes, including CHEK2, ATM, and PALB2 (Economopoulou et al., 2015; Dorling et al., 2021). These genes are involved in critical cellular processes such as DNA damage response and repair, which, when disrupted, can lead to increased cancer risk. The identification of these susceptibility genes has enabled the development of genetic testing panels, which are now widely used to assess individual risk and guide clinical decision-making (Couch et al., 2015; Cobain et al., 2016). 2.2 The impact of high-risk gene mutations, such as BRCA1 and BRCA2 Mutations in the BRCA1 and BRCA2 genes are among the most well-known and significant risk factors for breast cancer. These genes play a crucial role in the repair of DNA double-strand breaks through homologous recombination. When these genes are mutated, the DNA repair process is compromised, leading to genomic instability and increased cancer risk (Wisesty et al., 2020; Tacar et al., 2021). Studies have shown that women with BRCA1 or BRCA2 mutations have a significantly higher lifetime risk of developing breast cancer compared to the general population (Couch et al., 2015). Next Generation Sequencing (NGS) has facilitated the identification of novel variations in BRCA1 and BRCA2, further expanding our understanding of their role in breast cancer predisposition. For instance, novel variations such as 4448G>A (Ser1843Asn) in BRCA1 and 982dupA (Thr328AspfsTer) in BRCA2 have been identified, which may serve as useful markers for breast cancer diagnosis (Tacar et al., 2021). The clinical implications of these mutations are profound, as they not only inform risk assessment but also influence management strategies, including prophylactic surgeries and targeted therapies (Cobain et al., 2016). 2.3 Newly discovered genes and genetic polymorphisms associated with breast cancer Beyond BRCA1 and BRCA2, recent advances in genetic research have identified several other genes associated with increased breast cancer risk. High-penetrance genes such as TP53 and PTEN, and moderate-penetrance genes like CHEK2, ATM, and PALB2, have been implicated in breast cancer susceptibility (Dalivandan et al., 2021; Dorling et al., 2021). These genes are involved in various cellular processes, including cell cycle regulation, apoptosis, and DNA repair, highlighting the multifaceted nature of genetic contributions to breast cancer (Huang, 2024). Genome-wide association studies (GWAS) have also identified numerous low-penetrance susceptibility alleles that contribute to breast cancer risk. These common variants often lie in non-coding regions of the genome and affect gene regulation rather than protein function (Dalivandan et al., 2021; Boujemaa et al., 2022). For example, functional annotation of non-coding SNPs has revealed variants that alter the binding sites of regulatory elements, such as miRNAs and enhancers, which can influence gene expression and contribute to tumorigenesis (Boujemaa et al., 2022). The integration of these findings into polygenic risk scores holds promise for improving risk prediction and personalized prevention strategies in diverse populations (Dalivandan et al., 2021; Boujemaa et al.,
RkJQdWJsaXNoZXIy MjQ4ODYzNQ==