Normal Cells and the Formation of Cancer
Discussion of cell behavior, the role of DNA in regulating cell growth, and what goes wrong when cancer starts.Robert Weinberg, PhD
Daniel K. Ludwig Professor for Cancer Research
Massachusetts Institute of Technology
ROBERT WEINBERG, PhD
You might think that there's a central governor somewhere in the body that tells all the cells in the body how they should behave, but that's not the way things work. The fact is that each individual cell throughout the body is empowered to make important decisions, albeit decisions that are strongly influenced by its neighbors. And that empowerment, that license which individual cells are given, also represents a danger.
Well, as is the case with all forms of life, DNA is the master regulator here. Each of our cells carries within it a whole complement of genes, which instruct that cell as to when it should grow and when it should be quiet and not grow. In other words genes tell individual cells when is an appropriate time for it to proliferate--to grow and divide--and when it should cease and desist from growing and dividing. Now the DNA molecule that carries all this information is, like all other entities inside the cell, a physical object that is subject to damage, subject to corruption.
When these DNA sequences become damaged you get mutant genes and some of these mutant genes may begin to tell the cell to grow and divide inappropriately. In other words, a normal gene will tell a cell that it should stop growing, but a mutant gene--a damaged gene that has altered sequences in it--may tell a cell that it should start growing and dividing even though the conditions around the cell tell that cell to stop growing and to pull back from the program of growth and division.