What is the molecular basis of cancer?

Answer 1

Cancer is very difficult to explain in a medium like yahoo answers. But I will try to make it clear to you. So you understand how mitosis works, and that cells have a "cell cycle" system built into their DNA, and when this cell cycle says it's time for this cell to divide, it divides. It also tells cells that it's NOT time to divide yet.

Basically, the cell cycle works under the control of cell cycle regulating protein complexes called cyclins and CDKs. When this process of cell cycle control is lost by some kind of mutation, the cell loses control, and replicates uncontrollably.

Now, if it's built into DNA you might ask, how can different cells divide at different rates? Well cells are constantly in communication with each other by cell signaling (ligand/receptor or steroid hormones), and cell-cell adhesions. So there are various signaling pathways that originate outside the cell, come into the cell by some kind of signaling pathway, and tell the cell "this is how and when you are going to divide or not divide", and the cell transcribes the proper genes, and there you have it, control of the cell cycle!

For those who are unfortunate enough to have a mutation in a gene associated with the cell cycle itself, or a pathway that directs cell cycle regulation (a transcription factor like p53 is the best example we have), the cell cycle will not be properly regulated. So, we have named 2 types of genes that are implicated in cancer, "oncogenes" and "tumor suppressor genes". Oncogenes are genes that directly or indirectly tell the cell under normal conditions, "it's time to divide!", and tumor suppressor genes are genes that tell the cell "it's not time to divide". In normal conditions, the body's signaling pathways control both of these, and there is a fine balance. If there is a mutation in an oncogene, or a tumor suppressor gene, the cell loses control of it's cell cycle, and replicates uncontrollably!

You have to realize that MANY MANY pathways converge at the point of cell cycle regulation, way too many to list to you and explain to you, but it is important to recognize that it is a lot. And if something were to happen to just one of these pathways, the cell might lose its cell cycle control. This variety of pathways also explains occurrence of different types of cancers! Different cells rely on different signaling pathways to regulate their cell cycles.

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Answer 2

Uncontrolled growth is partly a description of cancer, but is uncorrect. For a tumor to fit the definition of cancer, it MUST have invaded surrounding normal tissue.

Mechanistically, the uncontrolled growth can happen in two broad categories:
1. Unregulated cell division
2. Escape/resistance to death signals

There are dozens of pathways that each of these events could occur, and usually, within any given cancer cell, there are multiple pathways incorrectly signalling.

Answer 3

Cancer is the cells that lost control on thier cell cycle and are left in a contineous series of divisions. moreover, these cells can escape their usual place and migrate "called metastasis" to other organs.
there are two basis for molecular understanding of cancer:
1) the two hits theory: for cancer to occur, both alleles of the tumor suppressor gene or proto-oncogene should be mutated. this is refered to as "loss of heterozygosity" or LOH.
2) cancer occurs after a series of mutations in different genes, in order for the cell to lose its control on division, in other words, cancer doesn't happen from one gene mutation alone.

Answer 4

In basic basic basic terms, a cell division has gone wrong and now the cells are dividing constantly and can't be stopped.
Why has the cell division gone wrong? DNA base changes from replication mistakes (it happens!) or UV light.....
How has the cell division gone wrong? There are so many theories and aspects of this that are being tested. Maybe a protein was made wrong and now is letting the cells grow.....
Hope that helps.......

Answer 5

There are many places for cancer to arise (in terms of the life of a cell). You're going to have to be more specific such as, do you want to know about a specific molecule and how it causes lack of control in the cell cycle?

Answer 6

You could be a bit more specific..... Cancer is just the uncontrolled reproduction of clls in the body.