What is the role of the p53 tumour suppressor gene in preventing cancer?

The p53 gene is a very important tumour suppressor gene found in almost every cell of the body. It produces a protein called p53 protein, which is also known as the "guardian of the genome". Its main job is to keep the cell healthy by checking the condition of the DNA. If any damage or mutation is found, p53 takes action to stop that cell from becoming a cancer cell.

How p53 Prevents Cancer

p53 protects the body from cancer in many ways. Here are its main roles:

1. DNA Damage Detection

  • p53 is always monitoring the DNA. When it finds any damage or mutation, it quickly becomes active. This is the first step. If such damage is ignored, the cell may continue dividing with mistakes, which can lead to cancer. So, p53 first detects problems and prepares the cell to respond.

2. Halting the Cell Cycle

  • Once damage is found, p53 stops the cell cycle to give the cell enough time to repair the DNA. It does this by increasing the production of a protein called p21, which blocks cyclin-CDK complexes. This pause mostly happens at the G1 checkpoint, but it can also occur at the G2 checkpoint. By stopping the cycle, p53 prevents the damaged DNA from being passed on during cell division.

3. Repairing Damaged DNA

  • During the pause, p53 helps the cell to repair its damaged DNA. It activates several repair genes. If the repair is successful, the cell is allowed to continue its normal cycle. This step is very important to stop mutations from becoming permanent.

4. Triggering Apoptosis (Programmed Cell Death)

  • If the DNA damage is too much and cannot be fixed, p53 activates the apoptosis pathway. This means the cell is safely destroyed before it can cause harm. p53 activates pro-apoptotic genes like BAX, PUM and NOXA. This step is very important in preventing damaged cells from turning into cancer.

5. Preventing Angiogenesis and Metastasis

  • p53 prevents cancer progression by blocking signals that promote angiogenesis, which is the formation of new blood vessels needed to supply tumours. It also inhibits metastasis, stopping cancer cells from spreading to other parts of the body. This helps in restricting tumour size and maintaining localised growth.




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