tell me abt p53 gene in cancer?

Answer 1

The p53 gene like the Rb gene, is a tumor suppressor gene, i.e., its activity stops the formation of tumors. If a person inherits only one functional copy of the p53 gene from their parents, they are predisposed to cancer and usually develop several independent tumors in a variety of tissues in early adulthood. This condition is rare, and is known as Li-Fraumeni syndrome. However, mutations in p53 are found in most tumor types, and so contribute to the complex network of molecular events leading to tumor formation.

The p53 gene has been mapped to chromosome 17. In the cell, p53 protein binds DNA, which in turn stimulates another gene to produce a protein called p21 that interacts with a cell division-stimulating protein (cdk2). When p21 is complexed with cdk2 the cell cannot pass through to the next stage of cell division. Mutant p53 can no longer bind DNA in an effective way, and as a consequence the p21 protein is not made available to act as the 'stop signal' for cell division. Thus cells divide uncontrollably, and form tumors.

Help with unraveling the molecular mechanisms of cancerous growth has come from the use of mice as models for human cancer, in which powerful 'gene knockout' techniques can be used. The amount of information that exists on all aspects of p53 normal function and mutant expression in human cancers is now vast, reflecting its key role in the pathogenesis of human cancers. It is clear that p53 is just one component of a network of events that culminate in tumor formation.

Answer 2

P53 is A Tumor supressor oncogene. This is an Important gene in the cell cycle- called check point gene. If this gene is Mutated or its expression is lost Cancer developes. In the cell, p53 protein binds DNA, which in turn stimulates another gene to produce a protein called p21 that interacts with a cell division-stimulating protein (cdk2). When p21 is complexed with cdk2 the cell cannot pass through to the next stage of cell division. Mutant p53 can no longer bind DNA in an effective way, and as a consequence the p21 protein is not made available to act as the 'stop signal' for cell division. Thus cells divide uncontrollably, and form tumors.
Many cancer particularly the GI cancers are related with mutation in P53 gene.one can see mutated P53 by Immunohistochemistry or by FISH or by DNA microarray technology directly in the cancer tissue in pathology

Answer 3

Hi Maddy. Padman gave you a lot of info. I would like to add a few basic concepts about p53.

1) Tumor suppressor p53 is called "The Guardian of the Genome" because it plays a central/major role in protecting the cell's genes from mutation.

2) p53 plays an important role in regulating the Cell Cycle (the process of cellular replication).

3) When DNA damage occurs, p53 is activated. Activated p53 stops the cell cycle to allow DNA repair mechanisms to repair any damaged DNA. If there is too much damage to the DNA, p53 will activate cell suicide (a process known as Apoptosis or Programmed Cell Death).

Hope you find this helpful. Best wishes and good luck.