Oncogenesis is the process by which cells undergo uncontrolled proliferation due to genetic and epigenetic alterations. The process is associated with the activation of proto-oncogenes and the inactivation of tumor suppressor genes. Defects in DNA repair systems increase genomic instability. Epigenetic modifications lead to disrupted gene expression. Loss of cell cycle control plays a critical role in tumor development. Impaired apoptosis mechanisms allow damaged cells to persist. Metabolic reprogramming meets the energetic demands of cancer cells. Tumor microenvironment supports proliferation and invasion. Immune evasion mechanisms enhance tumor persistence. Epithelial-mesenchymal transition is crucial in metastasis. Molecular profiling technologies enable the identification of individual tumor characteristics. In-depth study of oncogenesis contributes to early diagnostics and the improvement of targeted therapeutic strategies.