Science Weekly: New Discoveries About Cancer, the Brain, the Heart, and Digestion

Scientists are always finding new ways to understand how our bodies work. This week, researchers explored how to detect cancer earlier, what affects cancer risk, how malaria damages the brain, how the heart develops, and how animals digest food.

These studies used tools like advanced scans, genetic testing, and new ways to track food through the body. Their findings could help scientists improve health care in the future.

But there is an important difference between discovering something new and proving that a treatment works. Many of these findings are early steps toward better care.

Breast MRI Finds More Early Cancers, but Also Raises More False Alarms

Finding breast cancer early can help doctors treat it before it spreads. Two common tools for checking for breast cancer are mammograms and MRI scans.

A mammogram uses X-rays to look for changes in breast tissue. An MRI uses magnets and radio waves to create detailed pictures inside the body.

A study published in JAMA Network Open looked at breast cancer screening records from more than 105,000 women between the ages of 40 and 74.

Researchers found that MRI scans detected more early-stage breast cancers than mammograms.

For every 1,000 screenings:

• MRI scans found about 10 to 11 early-stage invasive cancers.
• Mammograms found about 2 to 3 early-stage invasive cancers.

However, MRI scans also caused more false alarms. A false alarm happens when a scan suggests that cancer might be present, but further testing shows that it is not.

For every 1,000 screenings, MRI led to about 93 to 94 recommendations for biopsies that turned out not to be cancer. Mammograms led to about 15 to 18.

A biopsy is a procedure in which doctors remove a small tissue sample to check for cancer.

The study also found that MRI did not clearly reduce the overall number of advanced breast cancers compared with mammograms. However, women who had received MRI screenings before had lower rates of advanced cancer than women getting their first MRI.

MRI can find more cancers early, but it also leads to more unnecessary testing. Doctors and patients need to weigh these benefits and risks when choosing a screening method.

How Body Weight and Genetics Affect Cancer Survivors

People who survive cancer sometimes develop a second, unrelated cancer later in life. Scientists want to understand what increases this risk.

A second study in JAMA Network Open followed more than 14,000 cancer survivors for about nine years.

Researchers looked at two possible risk factors:

• Genetics: Whether a person’s inherited genes made them more likely to have a higher body weight.
• Obesity: Whether a person had a body mass index (BMI) in the obesity range.

During the study, 722 people developed a second cancer linked to obesity.

People with a stronger genetic tendency toward higher body weight had a slightly greater risk of developing a second cancer.

However, having obesity was linked to higher cancer risk even among people who did not have a strong genetic tendency toward it.

In other words, genes were only part of the picture. A person’s body weight was also connected to their risk.

This does not prove that losing weight will prevent a second cancer. Other factors may help explain the results.

Understanding both genetics and body weight could help doctors give cancer survivors better advice about their long-term health.

What Happens Inside the Body When People Lose Weight?

When someone loses weight, changes happen throughout the body. But what exactly changes?

A study published in PLOS Medicine looked at small molecules in the blood called metabolites.

Metabolites are substances that the body makes or uses when it breaks down food, produces energy, and carries out other important jobs.

Researchers combined information from two weight-loss studies with genetic data. They found 242 metabolites that changed regularly as people lost weight.

Many of these changes involved fats, cholesterol-related particles, and amino acids, which help the body build proteins.

The researchers then studied how these changes might relate to different diseases.

Some changes involving LDL, often called “bad cholesterol,” were linked to heart failure risk. Changes involving HDL, often called “good cholesterol,” showed a more complicated picture. Some appeared helpful, while others were linked to greater risk.

The researchers also found connections between certain metabolites and osteoarthritis, a disease that affects joints.

However, the results did not work equally well for every disease, including kidney cancer.

Weight loss affects much more than the number on a scale. Studying these changes may help scientists understand why weight loss affects different diseases in different ways.

Scientists Find a Possible Way to Protect the Brain From Malaria

Malaria is a serious disease caused by parasites spread through infected mosquitoes.

In severe cases, malaria can affect the brain. This condition, called cerebral malaria, can damage blood vessels, cause bleeding, and become life-threatening.

Researchers reporting in Science Advances studied how the body’s immune system may contribute to this damage.

They focused on immune cells called CD8 T cells. These cells normally help protect the body by attacking infected or unhealthy cells.

But during cerebral malaria, the researchers found that these immune cells could also cause damage to the cells lining blood vessels in the brain.

A protein called RIPK1 appeared to play an important role in this process.

The researchers tested what happened when they blocked RIPK1 activity in mice with cerebral malaria.

The mice survived longer, even though the amount of malaria parasites in their blood did not change.

This suggests that blocking RIPK1 might protect blood vessels from damage without directly attacking the parasites.

The researchers also found signs of increased RIPK1 activity in brain tissue from people with cerebral malaria.

However, the treatment has not been proven to work in humans.

This discovery could lead to new treatments that protect the brain from damage caused by severe malaria. More research is needed before doctors can use this approach in patients.

How Small Changes in DNA May Affect a Baby’s Heart

The human heart begins developing long before a baby is born. This process depends on many genes working together at the right time.

Scientists are still learning why some babies are born with heart problems.

A new study created a detailed map of individual cells involved in human heart development.

Researchers identified 610 changes in DNA that were linked to congenital heart disease. Congenital means a condition is present at birth.

Interestingly, these changes were found in parts of DNA that do not directly provide instructions for making proteins.

Scientists once paid less attention to these areas. Today, they know that these parts of DNA can help control when and where genes are turned on or off.

The researchers used a gene-editing tool called CRISPR to test some of these DNA changes.

They found that certain changes affected how developing heart cells behaved.

One change near a gene called ETS1 affected how DNA was organized inside cells. It also caused some developing cells to move toward becoming blood vessel muscle cells instead of following their expected path.

Understanding how small DNA changes affect heart development could help scientists explain why some children are born with heart conditions.

What Lemurs Can Teach Us About Digestion

How long does food stay inside an animal’s body?

The answer depends on the animal, its diet, and how its digestive system works.

A study published in Royal Society Open Science explored this question by studying three types of plant-eating lemurs.

Researchers fed the lemurs leafy greens that contained special markers. These markers allowed scientists to track how long the food stayed in each animal’s digestive system.

The results showed clear differences.

Food markers appeared first in ruffed lemurs, followed by ring-tailed lemurs, and finally sifakas.

The shortest measured times for food to pass through the digestive system were:

• Ruffed lemurs and ring-tailed lemurs: About 24 to 30 hours.
• Sifakas: About 96 hours, or four days.

These differences may help explain how each species gets nutrients from its food.

They could also help scientists understand how animals spread seeds and germs through their environments.

For example, when an animal eats fruit, the seeds may travel through its digestive system before being left somewhere else. The time food spends inside an animal can affect how far those seeds travel.

Learning how animals digest food can help scientists understand nutrition, animal health, and the important roles animals play in nature.

The Bigger Picture: Small Discoveries Can Lead to Big Changes

This week’s research shows how much scientists can learn by looking closely at the body’s cells, genes, and chemical processes.

Better imaging may help doctors find cancer earlier. Genetic research may improve our understanding of disease risk. Studies of the immune system could lead to new ways to protect the brain. And even research on lemur digestion can teach us something important about biology.

But scientific discoveries take time.

A result in mice does not mean a treatment will work in humans. Finding a connection between two things does not prove that one causes the other. And a test that finds more signs of disease is not always the best choice for every patient.

The most important lesson is that science moves forward one discovery at a time. Each study adds another piece to our understanding of health, disease, and the living world.