Onkogénes

Onkogenes are genes that have the potential to cause cancer. In normal cells, these genes are called proto-oncogenes and they play a crucial role in cell growth, division, and differentiation. Proto-oncogenes regulate these processes by controlling cell signaling pathways. However, when a proto-oncogene undergoes a mutation or is amplified, it can become an oncogene. This transformation can lead to uncontrolled cell proliferation, a hallmark of cancer.

Oncogenes can arise from various genetic alterations. Point mutations, which are changes in a single nucleotide of the DNA sequence, can alter the protein product of the proto-oncogene, making it hyperactive or resistant to degradation. Gene amplification, where multiple copies of a proto-oncogene are present, leads to an overproduction of the encoded protein. Chromosomal translocations, which involve the rearrangement of genetic material between chromosomes, can place a proto-oncogene under the control of a strong promoter, resulting in its overexpression. Furthermore, viral insertions can sometimes activate proto-oncogenes by integrating their genetic material near these genes, thereby altering their expression.

The presence of oncogenes in a cell can disrupt the delicate balance of cell growth and death. This can lead to the formation of a tumor, which is an abnormal mass of tissue. Oncogenes are often described as "gain-of-function" mutations because they promote cellular activities that contribute to cancer development. Understanding the specific oncogenes involved in different types of cancer is vital for developing targeted therapies that can inhibit their activity and control tumor growth.