oncogénesis

Oncogenesis refers to the process by which normal cells are transformed into cancer cells. This transformation is a multistep event involving the accumulation of genetic and epigenetic alterations that disrupt normal cellular growth, differentiation, and death. These changes lead to uncontrolled proliferation, evasion of apoptosis, and the ability to invade surrounding tissues and metastasize to distant sites.

The fundamental drivers of oncogenesis are mutations in genes that regulate cell growth and division. Proto-oncogenes are normal genes that promote cell growth, and when mutated, they can become oncogenes, leading to excessive cell proliferation. Tumor suppressor genes, on the other hand, normally inhibit cell growth and repair DNA damage. Loss-of-function mutations in tumor suppressor genes can remove these brakes, allowing for uncontrolled cell division.

Epigenetic modifications, such as DNA methylation and histone modifications, also play a crucial role. These changes can alter gene expression without changing the underlying DNA sequence, potentially silencing tumor suppressor genes or activating oncogenes. Environmental factors, including exposure to carcinogens like tobacco smoke and radiation, as well as viral infections, can induce these genetic and epigenetic changes, initiating or promoting the oncogenic process. Viral oncogenesis specifically involves viruses that carry oncogenes or trigger cellular mutations. Understanding oncogenesis is central to cancer research and the development of targeted therapies.