Proteins are crucial in virtually all cellular processes, including cell cycle regulation, apoptosis, and DNA repair. Oncogenes and tumor suppressor genes encode for proteins that, when mutated, can lead to uncontrolled cell division and tumor growth. For example, the protein p53, known as the "guardian of the genome," is a tumor suppressor that regulates cell cycle and induces apoptosis in response to DNA damage. Mutations in the p53 gene can prevent these protective mechanisms, allowing cancer cells to proliferate. Additionally, overexpression of proteins like HER2 can drive aggressive types of breast cancer.
