Smoking and UV Damage Don't Affect Everyone Equally: This Study Explains Why

For many years, scientists have known that smoking, ultraviolet (UV) rays from the sun, and other environmental factors can damage DNA and increase the risk of cancer. However, one important question has remained unanswered: why do some people develop cancer after exposure to these risks while others do not?

A new study by researchers at the University of Cambridge has provided the strongest evidence yet that a person's inherited genes play a major role in determining how their body responds to DNA damage. The findings could change the way cancer risk is assessed and treated in the future.

What Did the Study Find?

Researchers discovered that inherited genetic differences influence how cancers develop after DNA damage. This means that two people exposed to the same amount of cigarette smoke or sunlight may not have the same risk of developing cancer.

The study showed that the genes people inherit from their parents affect how cells respond to DNA damage, how mutations build up, and how tumours evolve. This is the first direct evidence showing that inherited genetics can shape the course of cancer development after environmental exposure.

Why Do Some People Develop Cancer While Others Do Not?

Smoking and UV rays increase the chance of DNA damage in everyone. However, the body's ability to repair that damage differs from person to person.

People with certain inherited genetic traits may repair damaged DNA more effectively, reducing the chance that harmful mutations will accumulate. Others may have inherited genetic variations that make DNA repair less efficient, allowing damaged cells to survive and eventually become cancerous.

How Was the Research Carried Out?

The researchers carried out controlled experiments in mice with different genetic backgrounds. They exposed the animals to DNA-damaging factors and monitored how cancers developed.
Although the environmental damage was similar, the cancers followed different paths depending on the animals' inherited genes. This demonstrated that genetics influences not only whether cancer develops but also how it progresses. While the study was conducted in mice, scientists believe the findings are highly relevant to understanding cancer in humans.

What Could This Mean for Cancer Prevention?

The findings suggest that assessing cancer risk may need to go beyond lifestyle factors alone. In the future, inherited genetics could be considered alongside smoking history, sun exposure, family history, and other risk factors to identify people who would benefit from earlier screening or closer monitoring.

This approach could lead to more personalised cancer prevention programmes and improve early diagnosis.

Could the Findings Improve Cancer Treatment?

The research also suggests that patients may respond differently to treatments that work by damaging cancer cells' DNA, such as certain forms of chemotherapy and radiotherapy.
Understanding a patient's inherited genetic background could help doctors choose treatments that are more effective while reducing unnecessary side effects. This supports the growing move towards personalised cancer medicine.

Does This Mean Smoking or Sun Exposure Is Safe for Some People?

No. The researchers stress that smoking and excessive exposure to UV rays remain major causes of preventable cancer.

Even if some people have inherited genes that offer better protection against DNA damage, harmful environmental exposures still increase the risk of mutations and disease. Avoiding tobacco, protecting the skin from excessive sunlight, and following healthy lifestyle habits remain essential ways to reduce cancer risk.

Final Word

This study shows that cancer risk depends not only on environmental factors but also on the genes a person inherits. These inherited genetic differences influence how the body repairs DNA damage and how tumours develop over time. Although more research is needed.