Why do cells become cancerous?
An interview on cancer risk, causes, and treatment. Plus: What’s “preventive care”? + Cooling centers in your community
Welcome to Doing Well. Today:
A Q&A on how cancer develops and what we know about cancer risk
How new tools have made the deadliest type of skin cancer more treatable
Health news we’ve found useful this week
Word(s) of the week: preventive care
How to find—or support—a cooling center in your community
Let’s dive in.
We Asked: How does cancer develop?
According to the National Cancer Institute, 38.9% of people will be diagnosed with cancer at some point in their lives. This means that cancer will touch all of us: if not personally, then through someone we know or love.
At the same time, the death rate for cancer has decreased since the 1990s. This is largely thanks to advances in cancer treatment and screening, which allows disease to be detected earlier, when it's more treatable. Public education campaigns discouraging smoking (a major cause of lung cancer) and encouraging preventive measures like HPV vaccination (which can prevent cervical and other cancers) have also made a big difference.
I spoke to Dr. Joshua LaBaer—the executive director of the Biodesign Institute at Arizona State University and one of the country’s lead researchers in the field of personalized diagnostics—about why cancer develops and how to understand our risk for the disease. Our conversation has been edited for length and clarity.
Short on time? Here’s what to know
Cancer is a complicated genetic disease that develops when cells start breaking the rules for how they should behave. This rule-breaking, caused by genetic mutations, leads to cells dividing out of control, and sometimes moving to places they shouldn’t be.
Some cancers are inherited, which means someone is born with mutations in certain genes that can increase their risk for developing cancer. But most cancers are “sporadic”—the mutations happen during someone’s lifetime, randomly or as a result of factors like aging or environmental conditions.
If you have cancer in your family and you’re wondering whether you’re at higher risk, consider whether multiple members of your family have gotten the same type of cancer, and whether they got it at a young age. If so, you may be considered higher risk. You can check your risk level and get personalized screening guidelines here.
Evidence-backed ways to reduce your cancer risk include: getting recommended screenings, vaccinating against HPV and hepatitis B, trying to reduce processed foods in your diet, getting regular exercise, and avoiding smoking.
Mia Armstrong-López: What is cancer?
Joshua LaBaer: Cancer is a series of diseases—there's multiple cancers—in which the cells of our body stop behaving according to the rules for how cells should behave. Ordinarily, in an adult, we get a fixed number of cells. It varies very slightly, but it's a pretty steady state, because cells ordinarily obey the signals that tell them when to divide and when not to divide.
Cancer is a disease where cells don't follow those instructions, and they start to divide out of control. There are really two key characteristics that make cancer cancer. The first is that cells proliferate (multiply) when they should not be proliferating. And the second is that cancer cells don't obey the geographic rules of where they should belong—they start to invade places where they shouldn't be. Sometimes that invasion is local, where the tumor starts, and sometimes they break off, spread throughout the body via the bloodstream or other methods, and grow in other places.
MAL: Why do cells start breaking those rules?
JL: We know that cancer is a genetic disease, that’s to say, genes in these cells get mutated in such a way that the signal to proliferate (multiply) gets turned on and can't be shut off again, kind of like a light switch that's stuck in the “on” position. There are signals in the body that are there to stop cells from proliferating, those are called tumor suppressor genes. [When] those genes fail, their signals are shut off somehow.
The metaphor I often use is: Every cell has elements that look like the accelerator in a car, and elements that look like the brake in a car. The accelerators are like what are called oncogenes, and they get stuck in the on position. The pedal gets pushed to the floor, and it doesn't come back. It's stuck. The brakes are the tumor suppressor genes, and for some reason they fail, and the car starts rolling out of control. That's fundamentally what causes the cells to proliferate when they shouldn't.
MAL: You mentioned that cancer is a genetic disease. What do we know about the genes that cause cancer?
JL: There are two ways that it can happen. One is what's called inherited cancers. There are a number of syndromes in which people are born with mutated genes that predispose them to cancer, often at an early age. A classic example is the BRCA gene—this is a breast cancer gene. Women have a very high chance of getting cancer if they inherit that gene.
Most cancer is not that. Most cancer is what we call sporadic cancer—during the course of a person's lifetime, genes within certain cells will mutate and cause those cells to start to misbehave. We think that probably people are developing cancers often, but most of those cancers get taken care of by our immune systems and other systems in the body that catch them early and basically stop them from becoming full-on cancers. But every once in a while, the right mutations happen in the right genes, and they accumulate. It takes multiple mutations in a cell to lead to cancer; it's not just one gene. Those mutations occur one after the other, not necessarily right away, but over periods of years. And at that point, the cell starts to behave like a cancer cell and starts to grow out of control.
MAL: People hear a lot about things that they should and shouldn't eat, drink, or do to prevent cancer—it can be easy to get overwhelmed. Help us sort through this: Are there things we can do to lower our risk?
JL: It's complicated, and we don't have any simple answers. I generally tell people that a “heart healthy” diet is not a bad diet for cancer as well. Eating less processed food, trying to start with straightforward natural ingredients, making the food yourself. I would avoid eating too much saturated fat, eating excessive amounts of carbohydrates. Get exercise on a regular basis. You don't have to go run marathons, you just need to get out and move a few times a week. All the general recommendations apply. Personally, I'm a believer in eating a lot of vegetables. When I was in college, I did research on the protective effects of the cruciferous family—broccoli, cauliflower, brussel sprouts, cabbage. Eating some of that is not a bad idea, [but] they're not like magic pills. You want to eat a varied diet of healthy stuff—that's the best I can say.
MAL: The disease you're describing is so complex. “Eat this one thing” or “take this one pill” to prevent cancer—those simple solutions can't deal with the complexity of the problem.
JL: Nor is that really how cancer starts. Cancer is genes going wrong. It's mutations in genes or or various molecular mechanisms that shut genes on and off. A lot of it has to do with chance and exposure.
There are certain risky things, without a doubt. It’s almost impossible to overstate how bad smoking is. If you take smoking and you compare it to all of the other risk factors that have been listed to cause cancer or relate to cancer—high-fat diet, plastics, hormones—put those all together, they're not as bad as smoking. So any kind of smoked tobacco product, I would avoid.
Learn more about ASU’s research on cancer.
Well-Informed: Related stories from the ASU Media Enterprise archives
Melanoma is the deadliest form of skin cancer—but advances in how the disease is detected and treated have significantly reduced deaths. In this interview with Arizona Horizon on Arizona PBS, Dr. Mark Gimbel of the Banner MD Anderson Cancer Center discusses new treatments and steps you can take to protect your skin this summer.
Well-Versed: Learning resources to go deeper
People with certain jobs—for example, firefighters—are exposed to environmental factors that can increase their risk for cancer. In this Health Talk from ASU’s College of Health Solutions, experts discussed how we can make sure that workers and health care providers understand environmental risks and can take steps to reduce them.
Well-Read: News we’ve found useful this week
“Planning to Be Outside on a Hot Day? Take These Precautions,” by Clare Marie Schneider, June 19, 2025, NPR
“FDA Approves a Twice-Yearly Shot to Prevent HIV,” by Alice Park, June 20, 2025, TIME
“An Illustrated Guide to Inflammation in The Body,” by Nina Agrawal, June 19, 2025, The New York Times
Well-Defined: Word of the week
Preventive care
Preventive care, also known as prophylaxis, is the health care you receive to reduce your chance of becoming ill. This can include things like yearly check-up appointments with your provider, getting vaccinated, contraceptive counseling, and specific disease screenings, like mammograms for breast cancer, cervical cancer screenings, and certain blood tests.
Many people don’t get preventive care, but if you have access to services like annual check-ups, disease screenings, and vaccinations, it can significantly reduce your chances of illness later on. Most insurance plans are required to cover many preventive care services at no cost to you—you can check which services here. Seeking regular preventive care is an excellent choice for your health, and it’s also in everyone’s financial interest, as it can be a lot more expensive to pay for a hospital stay and emergency care later.
- Mel Moore, health communication assistant and ASU student
Well-Engaged: Protect yourself—and your community—from extreme heat
Last year, Maricopa County, Arizona reported 608 heat-related deaths. This tragic statistic demonstrates how devastating extreme heat can be for our health.
In addition to directly causing dangerous conditions like heat stroke, heat also amplifies the effects of other health conditions such as cardiopulmonary disease, diabetes, and mental health conditions. People with these underlying conditions are at a higher risk of heat-related illness and death, as are older adults and people who are unsheltered or without air conditioning.
This sounds like a daunting problem, and it is. But there are resources to help our communities get relief from the heat. Cooling centers can help people prevent or recover from heat illnesses and prevent heat-related deaths. They are available from May 1 to Sept. 30 all over Arizona. Anyone is able to use them at no cost, and no ID is needed for entry. You are welcome to pop in for a bottle of water or a longer stay, and some cooling centers may be able to provide basic medical care.
To find a cooling center in Arizona—or share a location with someone in need—consult this interactive statewide map or call 211. In Maricopa County, you can also visit maricopa.gov/heat, where you can find additional resources like energy bill assistance for those in need.
Want to be part of the solution? You can check-in on members of your community, volunteer to assist with heat relief programs, or donate bottled water or other resources.
Not in Arizona? Check this list to find a cooling center in your state.
-Kitana Ford, health communication assistant and ASU student
Do you have a question or topic you’d like us to tackle? Would you like to share your experience? Reach out at any time—we’d love to hear from you.