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June 3, 2025
Christine Bürg
- Health
Cancer researcher Hanna Heikenwälder: "Cancer is conquerable"
Molecular biologist Hanna Heikenwälder explains in the interview which preventative measures can protect against cancer and how AI can help
50 to 70% of all cancer cases could be prevented if the current state of research knowledge were properly implemented, writes Dr. Hanna Heikenwälder in her latest book "Cancer - The End of Fear." And that's not all. The molecular biologist, who researches cancer and aging at the University of Tübingen, is convinced that everyone can protect themselves from illness: through prevention and their own lifestyle. In our interview she talks about how we can live cancer-free in the future and what role AI and personalized medicine play in this.
Up until now, cancer has been considered an unbeatable disease. In your book, you give us all hope that in the future no one will have to die from it anymore.
Exactly. The point is that no one has to die from it anymore. Eliminating cancer from the world is, however, impossible because mutations and thus DNA changes are constantly happening in the body. The main goal is to prevent people from suffering or dying from cancer.
For a long time, we were overwhelmed by the incredible complexity of cancer, always lagging behind with our therapies, and the tumors, especially the advanced ones, continued to mutate. Through machine learning algorithms and AI, we are now able to handle this complexity. It is a matter of time how quickly we can implement this knowledge. And for this, we also need the help of politics and society as a whole.
Cancer is not a disease, but a process. What exactly do you mean by this statement?
I am aware that this statement is very provocative, especially for people who suffer from cancer. But it is important to prevent cancer. A disease always has something arbitrary. The word process is much more accurate because cancer, like aging, occurs in every human and every living being. So also in fish or plants. When you realize that cancer is a matter of when and where rather than if, preventive measures take on a whole new value in our society.
© André Leisner
Dr. Hanna Heikenwälder studied molecular biology in Lübeck and the USA before earning her doctorate at the TU Munich on the connections between inflammation and cancer development in the intestine. She is currently researching cancer and aging at the University of Tübingen.
Only about 5 to 10% of all cancer cases are caused by congenital genetic defects, while the remaining 90 to 95% are due to genetic changes that we acquire over the course of our lives. What causes these changes?
To override all the security and protective mechanisms of our body, it takes about five genetic changes in a cell to mutate into a malignant cancer cell. In most cases, we only accumulate all these genetic changes over the course of our lives, and of course, carcinogens also play a role. Smoking, UV radiation, or alcohol, for example.
What many people do not know is that there is a second type of cancer-causer called cancer promoters. These prevent genetically damaged cells from dying, which is what they normally do, or they promote the growth of these cells. And these cancer promoters are much more difficult to detect. This could be a lack of exercise, which harms the immune system, diet, or an altered sugar metabolism.
You can protect yourself from cancer promoters through prevention. For example, you need to smoke for decades before you get lung cancer. You have to sunbathe for decades to develop skin cancer. But cancer promoters have a lasting effect on all cells that have genetic damage, regardless of whether it is congenital, caused by lifestyle or unhealthy habits. Or whether it, like in most cases, simply arises spontaneously and on its own.
This means that everyone carries precursors of cancer within themselves, but they do not necessarily mutate into cancer cells. What can individuals do to protect themselves from this?
Cancer diseases have an incredibly high number of unreported cases. Around 5% of men around the age of 30 already have precursors of prostate cancer, and by the time they are 69 years old, it is almost 60%. In the intestine, it is the polyps. Only a small proportion of these become malignant, about 11 to 15%. The fact is that cancer originates from normal body cells and every cancer disease has a stage where it is benign and well treatable. However, if you wait too long, it progresses to a malignant stage where it is extremely difficult or no longer treatable.
It is important that we recognize the malignant from the benign precursor stages. In the future, AI will help us with this. For example, AI now recognizes skin cancer better than a dermatologist. I can feed mammography images into a database, along with other parameters like blood, etc., and see the course.
If we were to implement this everywhere from now on, we could create incredibly meaningful algorithms with our technical possibilities in the shortest possible time that could tell us: This tumor will become malignant, or this one is benign. These are information and patterns that AI recognizes and that we could not recognize with the human eye.
In Tübingen, we have one of the largest research centers for AI in Europe. So we have the capabilities and do not need to wait for these innovations to come from other countries. We are responsible for generating them. We need to detect cancer and prevent painful therapies.
It is also fascinating to say that aging is a protective mechanism against cancer. What does that mean?
When looking at the distribution of cancer diseases, it becomes clear that they go up throughout life and reach their peak at around 70 to 80 years. One might think that cancer is a classic age-related disease. Which is true, but the opposite is also true. Aging is actually a consequence of or an evolutionary protective mechanism against cancer.
The fact that our cells do not live forever and only have a limited potential to divide (they stop growing after about 50 divisions) is an ingenious mechanism of evolution. When the cell-protective caps, the telomeres, are used up, the DNA strand is exposed, which is a severe DNA damage. The affected cells do not die, but stop growing. These are called senescent cells.
When we are young, we still have a fourth immune system. It recognizes and eliminates these cells. The immune system not only protects us from bacteria or viruses, but also plays a very important role in the detection and elimination of cancer cells. The miracle of spontaneous healing, which we always hope for, actually happens a thousand times a day in our bodies, although we don't notice it.
The problem in old age is not only that we have accumulated many genetic changes, but that one of the first organ systems that ages is the immune system. And that is the fatal part. The number of aged or damaged cells increases, while the immune function decreases.
Dr. Hanna Heikenwälder explains in her book, among other things, why we need to understand how cancer develops in order to prevent its outbreak, and which small lifestyle changes can have great effects against cancer.
To fight cancer, personalized medicine is needed. What exactly does that mean?
In English, it's also called precision medicine, which means targeted. At the moment, cancer therapy is decided based on the type of tumor, for example, colon or breast cancer. Mostly a standard therapy, although it is often known beforehand that it only works in 40% of patients. If it doesn't work, the next one is taken. With our current capabilities in gene sequencing and proteomics (the study of proteins), predictions could be made as to whether this therapy works or not.
We need AI for this because the amount of data is far too large for us to process. Cancer is a common disease, but every tumor carries different genetic changes and every person brings different genetic predispositions, has a different immune system, reacts differently to drugs, which also depends on the microbes in the gut.
All this knowledge must be included in the therapy decision. This is the case in a center for personalized medicine whose heart is the molecular tumor board of interdisciplinary experts – geneticists, bioinformaticians, pathologists, surgeons – who use data from machine learning algorithms to make the ideal therapy decision.
We can not only treat patients more specifically, but also collect new knowledge and derive new drugs from it and tailor an immunotherapy. What comes with personalized medicine will exponentially accelerate our progress in cancer therapy because we are able to handle this complexity. We can anticipate resistance based on this data. Now it's really just about implementation.
What do you think is important and necessary for your vision to become a reality and for no one to die of cancer anymore?
Education is very important because we need society and politics for implementation. I believe that prevention should begin as early as possible, already in childhood. Schools are the ideal place because all children go to school. And it is also the ideal time to teach children routines that they can take with them later in life - like brushing their teeth.
A daily sports routine, for example, is not only good in terms of cancer prevention, but also helps reduce stress. It enhances mood and is good for the brain, it improves concentration and performance. Sport has so many benefits. It protects against more than 35 chronic diseases.
The WHO says children of school age should do an hour of sport a day. Why doesn't this happen in schools? I think there needs to be an incentive, an award for active schools, for sugar-free schools in the form of funding, for example. School nurses are also a great concept for me. They provide personalized prevention on a small scale.
Often you can already see in childhood who the patients of the future are or who needs more guidance. Also, a school subject on health, where children learn what healthy eating is, how the immune system works, what a vaccination is. But also: Where can I find help? Where do I go if I don't feel well mentally? Where if I don't feel well physically? We have already discussed a weekly health subject in school with the ministry in Baden-Württemberg.
Keyword lifestyle measures that protect against cancer. Which ones are particularly important?
The lowest cancer risk and the lowest overall mortality are associated with a normal BMI. In terms of cancer risk, it should even be in the lower range. There are very large studies with 2 million never smokers, i.e., people who have never smoked. You can clearly see that being overweight increases the risk of cancer.
It is only from the age of 80 that this effect levels off. But that is not because being overweight suddenly protects, but because pathological processes increase with age, which blurs the effect of body weight.
Low body weight is therefore important, as are meal breaks, especially at night. The rule that you should eat like a king in the morning and less and less towards the evening is actually true. It's not just about the amount of calories. If you constantly consume small amounts, there is always insulin secretion.
Foods with a low glycemic index are actually a good choice because they keep you full longer and ensure that carbohydrates are released into the blood more slowly. The advantage of this is that you don't have such high insulin peaks or insulin is released strongly. And incidentally reduces the risk of diabetes.
I am often asked whether it is better to eat a vegetarian diet. Yes, provided you follow certain rules. If you only eat pudding or sweets, that's obviously not healthier. But in general, plant proteins are more beneficial in terms of cancer risk than animal proteins. Red meat is considered possibly carcinogenic according to the WHO.
What role does sleep play?
A certain amount of sleep is important. The lowest cancer risk is observed between six and a half and seven hours of sleep, the lowest overall mortality at about 7.5 to 8 hours. What many people don't know: Too much sleep is also not healthy. From nine hours of sleep per night, overall mortality and cancer risk increase.
What preventive examinations do you recommend?
Definitely the legally recommended or the ones covered by the health insurance: colonoscopy, mammography, the preventive examination for early detection of prostate cancer, skin cancer screening. For women, of course, very important, is the gynecological examination, breast palpation, which should also be done by oneself because a large proportion of breast tumors are discovered by women themselves.
Also important: the Pap smear, which will be replaced by the HPV test in the future, as well as the HPV vaccination. The smear and vaccination complement each other. It is important to vaccinate boys as well because HPV not only causes cervical cancer but also penile cancer and cancers in the mouth and throat. I remind you of the story of Michael Douglas, who fortunately made this public as well.
And what many don't know: Anal cancer is also very often HPV positive, and most bowel tumors originate in the last centimeters of the bowel. This means that the HPV vaccination can probably also reduce the number of deaths from tumors in the last section of the bowel. Unfortunately, we currently have a participation rate of around 40% for girls, and it is significantly lower for boys, as far as I know, under 20%.
Frightening numbers. Does this vaccination have side effects?
As with any other vaccination, an autoimmune reaction may also occur here.
