Cancer is a common disease, so most families will have some members who have had cancer. This means even if cancer does not run in a family, a family member can still be at risk for some type of cancer in his or her lifetime.
Hereditary vs. Sporadic Cancer
Sporadic cancer and hereditary cancer differ in several ways that may affect health care decisions
Hereditary cancers are caused in part by gene mutations passed on from parents to their children. Other blood relatives may share these same gene changes. Sporadic cancers are believed to arise from gene damage acquired from environmental exposures, dietary factors, hormones, normal aging, and other influences.
Hereditary cancers can sometimes be more aggressive than the sporadic form of the same cancer. For example, hereditary prostate cancers tend to be more aggressive and more likely to spread than sporadic prostate cancers.
Individuals who have inherited a gene change may be at a higher risk for more than one type of cancer. For cancer survivors, this may affect cancer treatment options, prevention, or follow-up care.
Hereditary cancers are those caused by an inherited gene mutation that increases the risk for one or more types of cancer. "Hereditary Breast and Ovarian Cancer Syndrome" (HBOC) is most commonly caused by mutations in one of two genes: BRCA1 and BRCA2.
BRCA1 and BRCA2 mutations increase the risk for breast, ovarian, pancreatic, prostate, melanoma, and possibly other cancers.
HBOC does not only affect women having a BRCA mutations can increase a man’s risk for pancreatic cancer, melanoma, and an increased risk for aggressive prostate cancer. Just as Importantly, as with women, men can pass on their inherited mutation to their sons and daughters.
Can Cancer Be Prevented?
People with a genetic predisposition to develop certain cancers and others with a history of cancers in their genetically linked relatives currently cannot change their genetic makeup. However, genetic DNA assessments can help identify individuals who have a high possibility of developing genetically linked cancer who can take actions to possibly prevent cancer development.
Such actions can include closer and more frequent observation to help detect a cancer at an early stage when the cancer is more likely to be potentially cured with treatment. Such observations can include breast exams, testicular exams, colon-rectal exams, certain blood tests, prostate exams, urine tests and others.
An individual patient's unique personal and family circumstances should always be considered by doctors in making recommendations about ordering or not ordering genetic DNA assessments. Of course, people who have any suspicion that they may have cancer should discuss their concerns with their doctor as soon as possible
Early Detection is Critical
People with the following should discuss the possibility of genetic testing with a genetic counselor:
Why Take a Hereditary Cancer Test?
Because the genes we are born with may contribute to our risk of developing certain types of cancer, some people are genetically predisposed, and therefore, although they may not necessarily get cancer, they have a higher risk of developing the disease than those in the general population.
Additionally, these mutations are usually inherited from one or both parents and are present in nearly every cell of the body. Because hereditary mutations are present in the DNA of sperm and egg cells, they can be passed down in families.
Some of the Genes We Assess for Mutations and Why We Do
Women with mutations in the ATM gene have an increased risk for breast cancer, sometimes at relatively young ages. This increase in risk is not as high as the risk for women with mutations in the genes BRCA1 and BRCA2, but it is high enough to consider options to reduce cancer risk and increased screening to make sure that any cancers that do develop are caught as early as possible.
BRCA1 AND BRCA2
Breast cancer: About 12% of women in the general population will develop breast cancer sometime during their lives. By contrast, a recent large study estimated that about 72% of women who inherit a harmful BRCA1 mutation and about 69% of women who inherit a harmful BRCA2 mutation will develop breast cancer by the age of 80. Like women from the general population, those with harmful BRCA1 or BRCA2 mutations also have a high risk of developing a new primary cancer in the opposite (contralateral) breast in the years following a breast cancer diagnosis. It has been estimated that, by 20 years after a first breast cancer diagnosis, about 40% of women who inherit a harmful BRCA1 mutation and about 26% of women who inherit a harmful BRCA2 mutation will develop cancer in their other breast. Ovarian cancer: About 1.3% of women in the general population will develop ovarian cancer sometime during their lives. By contrast, it is estimated that about 44% of women who inherit a harmful BRCA1 mutation and about 17% of women who inherit a harmful BRCA2 mutation will develop ovarian cancer by the age of 80. In women, mutations in BRCA1 and BRCA2 increase the risk of several cancers in addition to breast and ovarian cancer. These include fallopian tube cancer and peritoneal cancer.
In men with BRCA2 mutations, and to a lesser extent BRCA1 mutations, are also at increased risk of breast cancer and prostate cancer. Both men and women with BRCA1 or BRCA2 mutations are at increased risk of pancreatic cancer. Certain mutations in BRCA2 (also known as FANCD1), if they are inherited from both parents, can cause a rare form of Fanconi anemia (subtype FA-D1), a syndrome that is associated with childhood solid tumors and development of acute myeloid leukemia
Women with mutations in the BRIP1 gene have an increased risk for ovarian cancer. We have only recently learned about this BRIP1-associate risk, so we do not yet know the exact size of the increase, but it may be as much as 5 times higher than the risk of ovarian cancer in women who do not have mutations in BRIP1. Women with mutations in BRIP1 also have an increased risk for breast cancer. The size of this increased risk may be small, but we do not yet know for sure. At this time, we do not know of any cancer risks for men with BRIP1 mutations. Women with mutations in BRIP1 can talk with their doctors and other healthcare providers about possible individualized recommendations such as special screening or, in the case of ovarian cancer, preventive surgery.
Deletions in EPCAM are inherited in an autosomal dominant manner, meaning each first degree relative (parent, child, and sibling) of an individual with this condition has a 50% chance of inheriting the disease-causing mutation and a 75% lifetime risk of developing colorectal cancer. Moreover, this syndrome is associated with a 30% risk of a second primary colorectal cancer arising within 10 years of the first. Women may also have an increased lifetime risk for endometrial cancer, but this risk appears to be much lower than what is typically seen with germline mutations in the mismatch repair genes. The risk for other tumor types typically seen in the Lynch syndrome is currently not thought to be increased. Germline deletions in EPCAM were only recently discovered as a cause of Lynch syndrome, therefore clarification of the risks of extra-colonic cancers in this condition will likely to occur as more individuals and families are identified.
Men and women with a mutation in MLH1 have a 52-82% lifetime risk (up to age 70) to develop colon or rectal cancer. Moreover, this syndrome is associated with a 30% risk of a second colon or rectal cancer appearing within 10 years of the first colon cancer. It is important to note that colorectal cancer risk remains higher after age 70. Women also have a 25-60% lifetime risk for endometrial cancer and 4-13% lifetime risk for ovarian cancer (up to age 70). People with Lynch syndrome are also at increased risk for other cancers that include cancer of the stomach, urinary tract, ovaries, small intestine, pancreas or bile ducts, sweat glands, and brain. Individuals with Lynch syndrome also tend to have more precancerous colon polyps that grow faster than individuals without Lynch syndrome. For this reason, anyone with Lynch should have frequent colonoscopies, even if they have several clear colonoscopies in a row.
People with mutations in both copies of their MUTYH gene have a condition known as MUTYH-associated Polyposis syndrome, or MAP. People with MAP have a high risk for developing large numbers of pre-cancerous polyps in their colon and rectum. An individual with MAP usually develops more than 10 and fewer than 100 polyps. Each of these polyps can develop into a cancer, and since there are so many of them, the risk for colorectal cancer is very high. Some people with MAP will develop colorectal cancer even without having many polyps. People with MAP also have an increased risk for small bowel cancer. What does it mean to have a mutation in only copy of the MUTYH gene?
People with mutations in the PTEN gene have a condition called PTEN Hamartoma Tumor Syndrome, or PHTS. In the past, people with PTEN mutations were sometimes given other diagnoses, depending on their individual symptoms. Examples include the diagnoses of Cowden Syndrome (CS), Bannayan-Riley-Ruvalcaba Syndrome (BRRS), PTEN-related Proteus Syndrome or Proteus-like Syndrome. We now know that all of these conditions are caused by mutations in the PTEN gene. People with PHTS have a high risk for female breast, endometrial, colorectal, melanoma, kidney, and thyroid cancers.
People with the following should discuss the possibility of a genetic DNA assessment with their doctor
Ovarian, fallopian tube, or primary peritoneal cancer
Breast cancer at age 50 or younger
Two separate breast cancers
A type of breast cancer called “triple negative breast cancer”
Male breast cancer
Prostate cancer at age 55 or younger or metastatic prostate cancer (cancer that spread outside the prostate)
People of Eastern European Jewish ancestry that have had any of the above cancers at any age
Especially, if more than one family member on the same side of your family has had:
Ovarian, fallopian tube, primary peritoneal cancer