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Some cancers are hereditary. Approximately 5–10% of all cancer cases are caused by inherited genetic mutations, changes in specific genes passed from parent to child that significantly elevate the risk of developing certain cancers over a lifetime. The most well-known examples include breast and ovarian cancer, linked to mutations in BRCA1 and BRCA2, and colorectal cancer associated with Lynch syndrome (American Cancer Society, Family Cancer Syndromes).
Inheriting one of these mutations does not guarantee cancer will develop. But it does mean that lifetime cancer risk can be significantly higher than the general population, and that knowing whether you carry one of these mutations changes what you can do about it. Proactive genetic testing, targeted surveillance, and informed medical planning are all available to people who choose to understand their inherited risk.
This guide explains which cancers are hereditary, what genes are involved, how to assess your personal risk, and what concrete steps to take if cancer runs in your family.
When a person is diagnosed with cancer, one of the first questions their family members ask is: "Could this happen to me?” The answer depends on the type of cancer, the family history pattern, and whether a hereditary mutation is present.
Most cancers (approximately 90–95%) are not directly caused by inherited mutations. They develop due to a combination of environmental exposures, lifestyle factors, and random DNA changes that accumulate over a lifetime. These are called sporadic cancers. A smaller but clinically significant group, roughly 5–10% of cases, is caused by inherited mutations present from birth and found in every cell of the body. These are hereditary cancers.
A cancer is considered hereditary when a germline mutation causes it, a change in DNA that is present in the egg or sperm and is passed down to children. Hereditary cancer mutations typically occur in genes that help repair DNA damage or regulate cell growth. When these protective functions are compromised, errors in DNA can build up over time, which may eventually disrupt normal growth controls and lead to cancer.
These three terms are often used interchangeably but describe distinct situations:
Understanding which category applies to a family history matters because it shapes the testing options, monitoring recommendations, and risk-reduction strategies available.
Not all cancer types carry equal hereditary risk. The following cancers have the most well-established hereditary link, with known genetic mutations that can be identified through testing.
Hereditary breast and ovarian cancer (HBOC) syndrome is one of the most studied hereditary cancer conditions. Mutations in either BRCA1 or BRCA2, both tumor suppressor genes, can raise the lifetime risk of breast cancer in women to as high as 72% and ovarian cancer to up to 44%, compared to roughly 13% and 1.2% in the general population, respectively. Men can also be affected by inherited changes in BRCA1 and BRCA2. Men who inherit a harmful change in either BRCA1 or BRCA2 have a higher risk of male breast cancer, prostate cancer, and pancreatic cancer.
Lynch syndrome is the most common hereditary colorectal cancer condition, caused by mutations in mismatch repair genes, primarily MLH1, MSH2, MSH6, and PMS2, along with EPCAM. It is responsible for approximately 3–5% of all colorectal cancer cases and can raise lifetime risk to as high as 80% depending on the gene involved.
Beyond colorectal cancer, Lynch syndrome is associated with an elevated risk for endometrial, ovarian, stomach, urinary tract, and several other cancers.
The hereditary cancer landscape extends well beyond breast and colorectal cancer:
Decades of research have identified dozens of genes associated with hereditary cancer risk. They are generally grouped by the extent to which they influence cancer development.
Penetrance describes the likelihood that a person with a given mutation will develop the associated condition. High-penetrance genes carry significantly elevated risk, often requiring proactive monitoring or clinical intervention. Moderate-penetrance genes still matter clinically but require individualized risk assessment.
The following are some examples of the most commonly tested high and moderate-penetrance genes:
Note: Lifetime risk figures are approximations based on published research and vary by specific variant, family history, and other factors. This table is for educational purposes. All risk assessments should be conducted with a licensed genetic counselor or physician.
The Centers for Disease Control and Prevention (CDC) designates certain genomic conditions as Tier 1, those with the strongest evidence for population-level benefit from genetic testing. Two of the three CDC Tier 1 conditions involve hereditary cancer: (CDC, Tier 1 Genomic Applications)
Tier 1 designation means that actionable interventions, increased screening, risk-reducing medications, and prophylactic surgery are available and evidence-supported when mutations are identified.
Kadance members receive access to hereditary cancer risk testing covering 26 genes through Kailos Genetics, its CAP-accredited, CLIA-certified laboratory partner. Every gene on the panel was selected based on strong scientific evidence linking it to increased cancer risk, drawing from established databases including CDC Tier 1 Genomic Applications, ClinVar, and ClinGen. All 26 genes have one thing in common: a positive result leads to a concrete, evidence-based clinical response for the member and their care team.
Most people with a hereditary cancer mutation don't know they carry one. Mutations are present from birth, produce no symptoms, and can be silently passed down across generations before a diagnosis brings them to light or before proactive testing reveals them.
Family history is the most accessible and most underutilized tool for assessing hereditary cancer risk. Medical guidelines from the American Cancer Society and the National Cancer Institute identify several patterns that may suggest a hereditary cancer syndrome: (NCI, Genetic Testing Fact Sheet)
A family history with one or more of these features warrants discussion with a physician and consideration of genetic counseling.
Hereditary cancer risk genetic testing analyzes DNA, typically from a cheek swab, saliva, or blood sample, for mutations in genes associated with elevated cancer risk. Panel testing has become the standard approach, examining dozens of relevant genes simultaneously rather than one gene at a time.
A comprehensive hereditary cancer panel may test for 20-80+ genes depending on the panel used. Results generally fall into three categories:
Your genetic information is private and protected, accessible only to you and your care team.
Genetic testing for hereditary cancer risk is appropriate for anyone who:
Testing is not only for people who have been diagnosed. It is increasingly used by prevention-oriented individuals who want accurate biological data to guide health decisions, particularly those who recognize that family history alone isn’t the whole picture.
Learning that cancer runs in your family, or receiving a positive genetic test result, is information. And information, when acted upon with the right clinical support, is an advantage.
A genetic counselor is a board-certified specialist trained to assess hereditary cancer risk, explain testing options, and help individuals interpret results in the context of their family history. For anyone with a concerning family history pattern or a positive test result, genetic counseling is the essential first step.
Genetic counselors help with:
For individuals with confirmed high-risk mutations, standard screening intervals are often insufficient. Medical guidelines recommend enhanced surveillance protocols:
The rationale is straightforward: when cancer is detected at its earliest stage, Stage 1, the localized, five-year survival rate can exceed 90% for many localized cancers. That number drops significantly when cancer is found after it has spread. Early, targeted surveillance makes early detection achievable. (NCI SEER Database)
For individuals at the highest inherited risk levels, additional risk-reduction options may be appropriate, discussed with and managed by a physician:
Precision health uses information about biology, including genetics, along with environmental, behavioral, and social factors to guide more personalized health decisions and interventions. Hereditary cancer risk testing is one of the most clinically validated applications of precision health available today.
For the roughly 1 in 3 individuals who will be diagnosed with cancer in their lifetime, the gap between what standard healthcare provides and what precision medicine makes possible is significant. Standard care rarely includes proactive genetic risk assessment unless prompted by a family history conversation or a personal diagnosis. Individuals who seek out that assessment independently may gain access to: (American Cancer Society, Cancer Facts & Figures)
No. Only 5–10% of cancers are caused by inherited mutations passed from parent to child. The majority of cancers are sporadic, caused by a combination of environmental exposures, lifestyle factors, and random DNA changes that accumulate over time. However, if a parent carries a hereditary cancer risk mutation, each child has a 50% chance of inheriting it.
Yes. Since most cancers are sporadic, the absence of family history does not eliminate risk. Additionally, hereditary mutations can be present in a family without a prior diagnosis if family members died young of other causes, if the mutation has variable expression, or if the relevant relatives have not yet been tested.
No. A positive BRCA1 or BRCA2 result means your lifetime risk of certain cancers, including breast and/or ovarian cancer, is significantly elevated, not that a diagnosis is inevitable. Many BRCA carriers live their full lives without developing cancer. The value of knowing is that it enables enhanced surveillance, earlier detection, and informed conversations with physicians about risk-reduction strategies.
Coverage varies widely and depends on the individual's health plan, their clinical history, and whether a genetic counselor has established medical necessity. The Genetic Information Nondiscrimination Act (GINA) offers some federal protections against discrimination by health insurers and employers based on genetic information, but it does not guarantee testing coverage. Individuals who pursue genetic testing proactively, outside of a clinical diagnosis, may not have costs covered. Consulting with a genetic counselor before testing can help clarify likely coverage and options.
Both BRCA1 and BRCA2 are tumor suppressor genes, and mutations in either elevate the risk of certain cancers, including breast and ovarian cancer. However, they are distinct genes with some differences in risk profile. BRCA1 mutations are generally associated with higher ovarian cancer risk and more aggressive breast cancer subtypes. BRCA2 mutations are more strongly associated with male breast cancer and pancreatic cancer.
Most people who carry a hereditary cancer risk mutation don't know it. Not because the information is unavailable, but because most healthcare systems are designed to react, not to proactively reveal what's already written in your biology.
Understanding whether you carry an inherited cancer risk mutation is one of the most concrete, actionable things you can do to make proactive health decisions. It doesn't require a diagnosis. It doesn't require a crisis. It requires curiosity and a willingness to act on what your DNA can tell you before something else does.
That’s why Kadance members receive access to hereditary cancer risk testing covering 26 genes, including BRCA1, BRCA2, and the primary Lynch syndrome genes, through Kailos Genetics, its CAP-accredited, CLIA-certified laboratory partner.
Every gene was selected based on strong scientific evidence from established sources, including CDC Tier 1 Genomic Applications, ClinVar, and ClinGen, and every result is actionable. Membership also includes genetic counseling to help interpret positive results and a clinical foundation for discussing findings with a physician.
This article is provided for educational purposes only and is not intended as medical advice, diagnosis, or treatment. Readers should consult a qualified healthcare professional with questions about their health, testing, or care decisions. The information in this article is general in nature and may not reflect the full scope, terms, or availability of services included in a Kadance membership.
