Oncogênese

Oncogênese refers to the complex biological process by which normal cells are transformed into cancerous cells. This transformation is driven by the accumulation of genetic and epigenetic alterations that disrupt normal cellular regulation. These alterations can affect genes that control cell growth, division, differentiation, and death, leading to uncontrolled proliferation and the potential for invasion and metastasis.

The process typically begins with a series of mutations. These mutations can arise spontaneously due to errors during DNA replication or be induced by environmental factors such as carcinogens found in tobacco smoke, radiation, or certain viruses. Once a critical number of mutations is reached, a cell can acquire oncogenic properties. These properties include the ability to evade growth suppressors, resist cell death, and stimulate its own growth.

Epigenetic changes, which alter gene expression without changing the underlying DNA sequence, also play a significant role in oncogenesis. These changes can silence tumor suppressor genes or activate oncogenes. The interplay between genetic and epigenetic modifications creates a cellular environment conducive to cancer development.

The progression of oncogenesis is a multi-step process. A single cell with a few mutations may not immediately become cancerous. Instead, it might undergo stages of pre-malignant growth, such as hyperplasia or dysplasia, before eventually becoming malignant. The accumulation of further genetic and epigenetic changes during these stages allows the cells to acquire the hallmarks of cancer, leading to the formation of a tumor. Understanding oncogenesis is crucial for developing effective cancer prevention and treatment strategies.