Why do a vast majority of biopsied tumors possess mutation? What type of gene is this?

Question

What does the gene normally do? And what are some characteristics of cancer cells?

Answer 1

There are two types of genes that are often mutated in tumors. Oncogenes, and Tumor Suppressor genes.

Oncogenes code for growth factors, and the mutations seen in tumors increase their activity or potency. Tumor Suppressor genes are involved in mitotic blocks or apoptosis. They basically stop cells from dividing, or cause them to self-destruct. Tumor Suppressor mutations render the genes ineffective.

Think of a cell like a car. In order for it to go out of control (become cancerous) it needs to let off the brakes and press down on the gas. Mutations in Oncogenes are like the gas pedal, because the cell to divide rapidly. Mutations in Tumor Suppressor genes are like cutting the brake lines, because they get rid of the natural blocks that prevent a cell from rapidly dividing.

Without any block to division, cells multiply out of control, and mutations crop up more and more. Many of the cells die (because the mutations make them non-viable) but many, many more survive and continue to divide. Many of the mutations remove even more of the error-checking and growth-restricting capabilities of the cell, leading to even more mutations.

Mutations will also enable the cancer cells to produce growth factors for blood vessels (the growth factors are normally produced by the cell, but sometimes mutations can cause the cell to produce too much of these growth factors). This leads to neovascularization and angiogenesis (growth of new blood vessels) within the tumor. As a result, these cells will receive more blood and nutrients, and will be more likely to survive (natural selection on a cellular level). Greater access to blood vessels also increases the chances that some cancerous cells will make it into the blood stream and metastasize to a different location in the body.

Basically, a tumor starts off as a mutated cell. Once it loses control over its growth, it begins to divide like crazy. It's offspring will mutate even further, and in the end, you have a population of cancer cells that, due to natural selection, are ideally suited to surviving and spreading throughout the body at the expense of the body's overall health.

Answer 2

in the complex process of cell division, many mistakes happen. there is a gene called "tp53" which either corrects these faults, or activates another gene which "kills" these mutant cells. in the absence, or depressed action of this tumour suppressor gene, the mutant cells grow and cause cancer. that is the reason for mutations in the biopsied tumour cells.

some properties of cancer cells are:
1) the ability to grow at a very fast rate (almost 10 times faster than normal cells!)
2) the ability to invade adjacent organs
3) the ability to enter blood vessels, &/ or lymph vessels
4) the ability to establish thmselves in any organ & grow in that tissue.