Ask A Scientist

How does cancer form?

Asked by: Haleigh Smith
School: St. James Middle School
Grade: 8
Teacher: Mr. Martinkovic
Hobbies/Interests: Dancing, cheerleading, music and shopping
Career Interest: Pediatric oncologist

Answer from Susannah Gal

Associate Professor

Research area: Cancer cell biology, protein labeling and DNA computing Additional interests: Science and religion interaction, presentations to school and community groups on DNA topics PhD schools: Joint program at Johns Hopkins University and the Foundation for Advanced Education in the Sciences, National Institutes of Health Family: Husband and daughters, 19 and 14 Interests/hobbies: Contra dancing, music and travel Web page address:  

That's a good question and one currently being studied by many laboratories all over the world. Cancer cells form from normal cells when certain genes (sequences of DNA) are changed so that the way the cells grow (or die) is altered. Normal cells divide or reproduce until they touch another cell. Then they stay in a state of "suspended animation," not dividing but still alive. 

Cancer cells are altered in genes that control the growth process, so they keep dividing even when they touch other cells.  Also most normal cells die after a certain number of cell divisions. We think that this is controlled in part by DNA sequences located at the ends of chromosomes. Cancer cells can also form when genes controlling the cell death process are altered. Then the cancer cells don't die as normal cells do.  

There are 3 main types of genes that can change to form cancer cells from normal cells. They're like parts of a car.  Some of these are like a car's accelerator, but stuck giving gas even if you want the car to stop, called oncogenes.  There are other genes like a car's brakes that when altered, don't work to stop the car.  These genes are called tumor suppressors.  The third type are genes like a car mechanic keeping the car running smoothly. When these genes are altered, this can result in DNA changes to the oncogenes or tumor suppressors.  Usually cancer forms when there are changes to a few of these kinds of genes, not just one.  

A lot of cancer research, including the work being done in my laboratory at Binghamton University (, studies these gene changes and how those result in cancer. We hope to develop diagnostic ways to analyze cancer cells and new drugs to help block cancer cells from growing.  Maybe someday you can help with that work.

Last Updated: 3/1/17