Apr 19, 2024 - Health + Traits

Understanding the Risk Is the First Step in Preventing Cancer

Family Health Survey Graphic

As part of National Cancer Prevention and Early Detection Month, 23andMe is joining other voices in April to raise awareness. 

By sharing insights with our customers about cancer risk, we aim to highlight the importance of knowing one’s family health history, getting appropriate cancer screenings, and understanding the role of genetics and lifestyle in cancer risk.

“Probably the most important thing 23andMe does is help people understand whether they have an increased likelihood of cancer based on their genetics, often information that they would not have known otherwise,” said Noura Abul-Husn, MD, PhD, Vice President of Genomic Health at 23andMe. “But we also highlight for everyone the importance of family health history and other factors that contribute to cancer risk.”

23andMe does not diagnose cancer, but thousands of 23andMe customers have learned of their genetic likelihood of developing different forms of cancer.* This, in turn, has empowered them with information that they and their doctors can use to take preventive steps and personalize care. Those steps might include confirmatory testing of genetic risk, earlier or more frequent cancer screenings, or, when necessary, preventative surgery. Sometimes, the next steps might focus more on changes in diet and exercise to help reduce risk and prevent cancer.

Finding out early about a risk, or learning that you have cancer in the very early stages, offers the most potential for prevention or treatment. Large numbers of individuals who are at risk, or may be in the early stages of cancer, remain unaware. 

One study in 2019 found that almost a quarter of prostate cancers and about a third of breast cancers are diagnosed in the late stage of the disease. Unfortunately it’s likely that for other cancers that may be harder to detect or for which screening is not as readily available, the percentage of those that are only detected in the later stages is even higher.

Taking Action

At 23andMe, we’ve also seen firsthand the transformative power this knowledge has given people.

This includes people like Kenzie and her mom, Shannon. Kenzie learned from her 23andMe BRCA1/BRCA2 (Selected Variants) Genetic Health Risk Report* that she had a BRCA1 variant that put her at a much higher risk for breast, ovarian, and other cancers. Her mom, Shanon, had gone through treatment for a form of blood cancer when Kenzie was in her teens. Because of her cancer history, Shannon made an appointment with her oncologist, where she shared the news about Kenzie’s report. She was referred to a genetic counselor, who immediately set Shannon up for genetic testing. Kenzie also got confirmatory testing. It turned out that both mother and daughter carry the BRCA1 variant putting them at higher risk for cancer. 

Shannon said that learning of her and her daughter’s genetic risk for cancer was transformative and allowed them to work with their doctors to take action. 

“I think for me, how quickly we were able to move through this process to take control, that’s powerful,” said Shannon. “When I feel a little deflated or sad that Kenzie has this (risk), I worry about her; Kenzie reminds me of how blessed we are to have this knowledge. Look at what we’ve been able to do, not to get breast cancer. It’s an inspiration.”

For Shannon and Kenzie, addressing their risk meant preventive surgeries and more frequent cancer screening. Other individuals may choose different options depending on their risk, but knowing one’s risk is the critical first step in prevention. 

Cancer and Genetics

Up to ten percent of all cancers are due to inherited genetic variants passed down through families. In genes like BRCA1 and BRCA2, these variants significantly impact cancer risk.

For people with these highly impactful variants, clinical guidelines recommend enhanced screening and, in some cases, preventive surgeries and medications. But most people with these variants don’t know they have them.

For example, studies have found that more than 80 percent of people with a BRCA1 or BRCA2 variant don’t know they have it. Many do not have a family history of cancer that would qualify them for traditional genetic testing through a healthcare professional. Layered onto that are disparities in access to BRCA1/2 genetic testing in some communities in the U.S., including the Black, Hispanic/Latino, and Asian communities.

We’ve heard from many customers who learned they had a BRCA variant through 23andMe. This includes Ann, whose knowledge allowed her to make a decision about her body from a place of being healthy. Sarah’s 23andMe report alerted her and her doctors and allowed her to catch her breast cancer at a very early stage. There’s also  Laura, who said that finding out she had a BRCA variant gave her a chance to “change (her) destiny.” 

Other Factors

Thankfully, variants with a big impact on cancer risk are relatively rare — for example, about 1 in 200 people in the general population has a BRCA1 or BRCA2 variant. However, these variants are more common in certain populations, such as people with Ashkenazi Jewish ancestry.

For people without a high-risk variant, genetics can still play an important role. In these cases, the chances of developing cancer are influenced by thousands of common variants that each have a small effect. It’s these common genetic variants combined with lifestyle and environment that increased the likelihood of a majority of cancer.

Non-genetic factors that impact cancer risk include such things as ultraviolet radiation from the sun, smoking tobacco, chemical exposures, viruses, or other carcinogenic exposures that damage cells and could trigger the growth of cancer. 

Understanding one’s risk and the mix of genetic and non-genetic factors in that risk can also highlight that we are not powerless. Estimates suggest that about 30 percent of cancers are preventable through making healthier choices, whether it’s stopping smoking, limiting alcohol consumption, or getting enough exercise. 

But cancers can also happen to people who make all the right choices around diet and exercise, and who don’t have any known genetic risk factors. For example, non-smokers can still get lung cancer. This is one reason why early detection — through routine screening and talking with a healthcare professional about any new or concerning symptoms — is so important. 

Each cancer is different but they all share something in common: a disruption of the normal process of cell division and growth in our bodies. Cancer hijacks this process, allowing abnormal cells to grow, divide, and metastasize into other body parts. 

Left unchecked cancer can spread throughout the body making it very difficult to treat. That’s why improved early screening for cancers and access to healthcare are also so crucial in preventing cancer and detecting it early.     

Knowledge is Power

Caught early, most cancers are treatable. But catching cancer early — or preventing it entirely — requires better screening or knowing who may be at the higher risk because of a genetic risk for cancer, or a family history of cancer, or because of lifestyle or environmental exposures.

Something as simple as learning your family’s cancer history is tremendously important. Just consider that the risk for breast cancer nearly doubles if a sibling or parent has ever had breast cancer, for instance. 23andMe offers tools for tracking family health history. There are also other tools for tracking this information including the free online tool from the Surgeon General called My Family Health Portrait.  

Sometimes, the information we learn from our family history or from genetic testing can be life-changing. Other times, information from genetic testing can be more subtle than that, nudging us toward healthier actions. Learning your genetics increases your likelihood of developing skin cancer, for example, reminds you to be more diligent about sunscreen, and can motivate you to follow through on seeing a dermatologist for regular skin checks. 

Learn More

23andMe provides customers with two types of genetic reports on cancer.

In our Genetic Health Risk reports, we report on individual variants with a big impact on cancer risk. These reports include our BRCA1/BRCA2 (Selected Variants) report*, which tests for 44 variants associated with a higher risk for breast, ovarian, prostate, and pancreatic cancer; our MUTYH-Associated Polyposis report*, which tests for 2 variants that increase risk for colorectal cancer; and our 23andMe+ Premium Hereditary Prostate Cancer (HOXB13-Related) report*, which tests for one variant that increases risk for prostate cancer.

In our reports powered by 23andMe research, we use data from consented 23andMe research participants to develop polygenic scores that take into account thousands of common, small-impact variants to provide information about the chances of developing cancer. For 23andMe+ Premium members, we currently offer this type of report on some of the most common types of cancer: breast, prostate, and colorectal cancer, along with two reports related to skin cancer (basal and squamous cell carcinomas, and melanoma). For each of these cancer reports, 23andMe offers follow-up recommendations. 

Find Out More

Learn more about all that 23andMe has to offer and compare our services here.


23andMe health predisposition reports include both reports that meet FDA requirements for genetic health risks and reports which are based on 23andMe research and have not been reviewed by the FDA. The test uses qualitative genotyping to detect select clinically relevant variants in the genomic DNA of adults from saliva for the purpose of reporting and interpreting genetic health risks and reporting carrier status. It is not intended to diagnose any disease. Your ethnicity may affect the relevance of each report and how your genetic health risk results are interpreted. Each genetic health risk report describes if a person has variants associated with a higher risk of developing a disease, but does not describe a person’s overall risk of developing the disease. The test is not intended to tell you anything about your current state of health, or to be used to make medical decisions, including whether or not you should take a medication, how much of a medication you should take, or determine any treatment. Our carrier status reports can be used to determine carrier status, but cannot determine if you have two copies of any genetic variant. These carrier reports are not intended to tell you anything about your risk for developing a disease in the future, the health of your fetus, or your newborn child’s risk of developing a particular disease later in life. For certain conditions, we provide a single report that includes information on both carrier status and genetic health risk.

Warnings & Limitations:

The 23andMe PGS Genetic Health Risk Report for BRCA1/BRCA2 (Selected Variants) is indicated for reporting of 44 variants in the BRCA1 and BRCA2 genes. The report describes if a person’s genetic result is associated with an increased risk of developing breast cancer and ovarian cancer and may be associated with an increased risk for prostate cancer, pancreatic cancer, and potentially other cancers. The variants included in this report do not represent the majority of the BRCA1/BRCA2 variants in people of most ethnicities. The MUTYH-Associated Polyposis Genetic Health Risk Report is indicated for reporting the Y179C and G396D variants in the MUTYH gene and an increased risk for colorectal cancer. The two variants included in this report are most common in people of Northern European descent. The Hereditary Prostate Cancer (HOXB13-Related) Genetic Health Risk report is indicated for reporting the G84E variant in the HOXB13 gene. The report describes if a person has the G84E variant and if a male is at increased risk for prostate cancer. The variant included in this report is most common in people of European descent, especially in people of Northern European descent. These reports do not include variants in other genes linked to hereditary cancers and the absence of variants included in these reports do not rule out the presence of other genetic variants that may impact cancer risk. The PGS test is not a substitute for visits to a healthcare professional for recommended screenings or appropriate follow-up. Results should be confirmed by an independent genetic test prescribed by your own healthcare provider before taking any medical action. For important information and limitations regarding all genetic health risk reports, visit https://www.23andme.com/test-info.

Stay in the know.

Receive the latest from your DNA community.