| MadSci Network: Cell Biology |
As with everything else in science, there is a short answer and there is a long answer. For clarity, let's start with the definitions.
I included both mutagen and mitogen, because they are spelled similarly (i.e. easy to confuse), and because mitogens fill some of the gaps that answer your question.
Cancer, as you know, is the abnormal growth of cells; more specifically, cancer cells are normal body cells that have lost the ability to properly control their growth. One way that this can happen is for something foreign, like a virus or parasite or a chemical substance, to tell the cell to start dividing. Another way is for something to happen inside the cell that changes the signals coming from the genes that control how the cell grows. One way to change genetic signals is to mutate the genes that send the signals: this can be caused by something that causes the genes to mutate, or through the natural mutations that can occur whenever cells divide. In cancer cells, we always see changes in the signals that control cell growth, cell division, and cell death; however, we don't always see mutations in the genes that send these signals, and often the mutations we do see are caused by large chromosomal changes that were not caused by mutagens.
So:
Mutagens can cause cancer - be carcinogenic - sometimes, but only if precise
genes are mutated; most of the time, mutations cause cells to die. Mitogens
can cause cancer - be carcinogenic - sometimes, but only if during the forced
cell divisions the cells gain mutations that make them cancerous; often, the
excessive division causes them to burn out and die. Carcinogens
cause cancer, as determined statistically by linking exposure to the carcinogen
to incidents of cancer, and it is still unknown how many carcinogens work,
since they are neither mutagens nor mitogens.
Try the links in the MadSci Library for more information on Cell Biology.