A scientist lowers biological samples into a liquid-nitrogen storage tank at the Cancer Research UK Cambridge Institute.Dan Kitwood/Getty Images/Cancer Research UK
- Cancer is a leading cause of death, with more than 1.8 million new cases annually in the US.
- Many factors contribute to cancer, like genetics, and it's not clear what causes individual cases.
Every year, about 1.8 million people in the US are diagnosed with cancer. About 600,000 people die from the disease annually, which makes it the second-leading cause of death in the country after heart disease.
Scientists don't fully understand how cancer works or what causes individual cases. It's difficult to pinpoint the origins of cancer because many factors are involved, including genetics, environment, lifestyle, and even your job.
Research this year found links to cancer in our everyday lives.
Known cancer-causing chemicals continue to show up in unexpected places, including household items, because of industrial contamination. Researchers are also starting to better understand the health implications of other toxins, such as pesticides. Evidence from this year suggested pesticides were linked to cancer decades and generations after exposure. And lifestyle habits like what we eat, drink, and do also play a role in our risk of cancer and when it might develop.
While intriguing, the evidence doesn't directly point to what causes cancer, but understanding correlations can help scientists come up with future research questions to better our knowledge of the disease and how to prevent it.