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What is a TP53 mutation?

TP53 is a tumor suppressor gene that codes for the protein p53, often referred to as the "guardian of the genome". I think of it like a stop light. The p53 protein plays a crucial role in maintaining the integrity of the genome by regulating cell cycle progression, apoptosis, senescence, DNA repair, and angiogenesis. When DNA damage is detected, p53 is activated and it halts the cell cycle to allow for DNA repair. If the damage is too severe and cannot be repaired, p53 can trigger programmed cell death, or apoptosis, to prevent the propagation of the damaged DNA. Mutations in the TP53 gene can lead to the production of an altered p53 protein that is unable to perform these functions effectively. This can result in the accumulation of DNA damage and genomic instability, which can lead to uncontrolled cell growth and proliferation, a hallmark of cancer. In addition, some TP53 mutations can result in the production of a mutant p53 protein that not only loses its tumor suppressor functions, but also gains new oncogenic functions that promote cell survival, angiogenesis, and invasion. Therefore, TP53 mutations can contribute to cancer development and progression through a combination of loss of tumor suppressor functions and gain of oncogenic functions. The frequency of TP53 mutations varies widely depending on the type of cancer. In general, TP53 is one of the most frequently mutated genes in human cancers. Here are some estimates: In ovarian cancer, TP53 mutations are found in up to 96% of high-grade serous carcinomas, the most common subtype of ovarian cancer. In colorectal cancer, TP53 mutations are found in approximately 50-60% of cases. In breast cancer, TP53 mutations are found in approximately 20-30% of cases overall, but the frequency can be much higher in certain subtypes. For example, in triple-negative breast cancer, TP53 mutations are found in up to 80% of cases. In lung cancer, TP53 mutations are found in approximately 50% of non-small cell lung cancers and up to 90% of small cell lung cancers. In head and neck squamous cell carcinoma, TP53 mutations are found in approximately 60-80% of cases. Some people have somatic (acquired) TP 53 mutations and some people have germline (inherited) TP mutations. Somatic and inherited (germline) mutations in TP53 have different origins and implications: Somatic TP53 mutations: These are acquired during a person's lifetime and are present only in the tumor cells. They are not present in every cell of the body and they cannot be passed on to offspring. Somatic TP53 mutations are very common in cancer. TP 53 mutations are found in approximately 50% of all human cancers, making TP53 one of the most frequently mutated genes in cancer. Most of these mutations are acquired (somatic). The frequency can vary depending on the type of cancer. For instance, in ovarian and colorectal cancers, TP53 mutations can be found in up to 50-60% of cases. In lung cancer, the frequency can be around 30-50%, and in breast cancer, it's approximately 20-30%. Inherited (germline) TP53 mutations are less common and are present in every cell of the body because they are inherited from a parent. They can be passed on to offspring. Germline (inherited) TP53 mutations are much less common than somatic TP53 mutations. Inherited TP 53 mutations are associated with Li-Fraumeni syndrome, a rare hereditary cancer syndrome. The prevalence of Li-Fraumeni syndrome is estimated to be about 1 in 5,000 to 1 in 20,000 in the general population. It's important to note that a person with a germline TP53 mutation has an increased risk of developing cancer, but not everyone with a germline TP53 mutation will develop cancer. The risk can be influenced by other genetic and environmental factors.