<p>Cancer is a complex and heterogeneous disease driven by a multitude of genetic alterations, including mutations, chromosomal rearrangements, and epigenetic modifications. Advances in genomic technologies have significantly enhanced our understanding of the genetic landscape of cancer, enabling the identification of key oncogenes, tumor suppressor genes, and DNA repair mechanisms that influence tumor progression. This review examines the molecular mechanisms underlying cancer development, focusing on the roles of mutations in genes such as TP53, KRAS, and EGFR. Furthermore, it explores the implications of genomic instability, tumor microenvironment interactions, and the emergence of precision medicine in oncology. The integration of next-generation sequencing and bioinformatics has facilitated the discovery of novel therapeutic targets, paving the way for personalized treatment strategies. Despite these advancements, challenges remain, including treatment resistance, tumor heterogeneity, and ethical considerations in genetic research. Addressing these complexities requires a multidisciplinary approach that combines molecular biology, bioinformatics, and clinical research. This review synthesizes current knowledge on cancer genetics, highlighting its importance in developing targeted therapies and enhancing patient outcomes.</p>