Clonal Evolution?

Question

Can someone give me a detailed explanation of the stages of oncogenesis and define the term "clonal evolution"? Thanks very much

Answer 1

Oncogenesis is a multi-factorial process that usually involves a predisposition with an underlying genetic abnormality. This may involve the presence of a proto-oncogene or a tumor-suppressor gene that is mutated. Usually a second mutation or genetic-level event provides the propellant to drive cells into a cancerous state.

These cancerous cells, because of the presence of the genetic mutations that provide for a survival advantage or become immortalized, begin to produce more and more copies of themselves (like "cloning"). This process of producing many identical copies of a cancerous cell is termed "clonal evolution" and begins the process of driving the malignant process onward into clinically apparent cancers.

Answer 2

Hi Loved One (Happy Valentine's Day!). I am going to disagree with some of the info. provided by the first answerer.

First, most cancers do not have a genetic predisposition. Researchers estimate that only 5 to 15% of all cancers have a hereditary component. Cancers result from accumulation of damage to a cell's DNA. Most of the time, all of the damage is a product of 'new injury' to the DNA and is NOT the result of inherited DNA problems.

Second, clonal expansion of a single damaged cell is the OLD theory of carcinogenesis that is now known to be incorrect. Clonal expansion is the idea that a single damaged cell replicates over and over to create a large mass of cells (a tumor) that are genetically identical. Research has shown that there is a great deal of genetic diversity in the billions of cells that make up a detectable tumor. Simply, no two cancer cells are genetically the same!

Carcinogenesis is believed to be a 3 stage process: 1) initiation, 2) promotion and 3) progression.

Hope this is helpful for you. Best wishes and good luck.