Populations at Risk

Most cancers occur by chance, often the result of lifestyle choices or environmental conditions. In some families, however, we see more cancer than might be expected to occur by chance alone. Determining which of these families has cancer related to an inherited gene mutation is important, as the cancer risks in hereditary cancer families are much higher than in the general population. These subgroups, or populations, as they are often referred to, may be organized along family lines, a single presence of a particular cancer, simultaneous occurrence of the same or different cancers in an individual, or previously identified mutations of certain cancer genes.

  • Sporadic Cancer - Cancer that occurs by chance. People with sporadic cancer typically do not have relatives with the same type of cancer.
  • Familial Cancer - Cancer likely caused by a combination of genetic and environmental risk factors. People with familial cancer may have one or more relatives with the same type of cancer; however, there does not appear to be a specific pattern of inheritance (e.g., the cancer risk is not clearly passed from parent to child).
  • Hereditary Cancer - Cancer occurs when an altered gene (gene change) is passed down in the family from parent to child. People with hereditary cancers are more likely to have relatives with the same type or a related type of cancer. They may develop more than one cancer and their cancer often occurs at an earlier than average age.

The following can be used to organize and identify people that are more at risk for hereditary cancer than the general population. These “red flags” are used to help identify whether someone is an appropriate candidate for testing:

Hereditary Breast and Ovarian Cancer:

  • Breast cancer diagnosed at age 50 or younger
  • Ovarian cancer at any age
  • Two primary breast cancers*
  • Male breast cancer
  • Triple Negative Breast Cancer
  • Pancreatic cancer with a breast or ovarian cancer*
  • Ashkenazi Jewish ancestry with an HBOC-associated cancer*^
  • Two or more relatives with breast cancer, one under age 50
  • Three or more relatives with breast cancer at any age
  • A previously identified BRCA mutation in the family

*In the same individual or on the same side of the family
^HBOC-associated cancers include breast, ovarian and pancreatic cancer

*Assessment criteria based on medical society guidelines.  For these individual medical society guidelines, go to www.myriadpro.com/guidelines.


Lynch syndrome:

An individual with any of the following PERSONAL histories*:

  • Colorectal or endometrial cancer before age 50
  • MSI High histology before age 60:
    • Mucinous
    • Signet ring
    • Tumor infiltrating lymphocytes
    • Crohn's-like lymphocytic reaction histology
    • Medullary growth pattern
  • Abnormal MSI/IHC tumor test result (Colorectal/Endometrial)
  • 2 or more Lynch syndrome cancers** at any age
  • Lynch syndrome cancer** with 1 or more relatives with a Lynch syndrome cancer**
  • A previously identified Lynch syndrome mutation in the family

An individual with any of the following FAMILY histories*:

  • Two or more relatives with a Lynch syndrome cancer**, one before the age of 50
  • Three or more relatives with a Lynch syndrome cancer** at any age
  • A previously identified Lynch syndrome mutation in the family

**Lynch-associated cancers include colon, endometrial, gastric, ovarian, ureter/renal pelvis, biliary tract, small bowel, pancreas, brain and sebaceous adenomas.

*Assessment criteria based on medical society guidelines.  For these individual medical society guidelines, go to www.myriadpro.com/guidelines.


Adenomatous Polyposis Syndromes:

  • Individuals clinically affected with FAP (100 or more colorectal adenomas)
  • Individuals with multiple colorectal adenomas (usually 10 or more cumulative adenomas)
  • Relatives of APC or MYH mutation carriers

*Assessment criteria based on scientific literature and expert opinion.  For a list of references, go to www.myriadpro.com/references.


Hereditary Melanoma:

  • Two or more melanomas in an individual or family
  • Melanoma and pancreatic cancer in an individual or family
  • Relatives of a p16 mutation carrier

*Assessment criteria based on scientific literature and expert opinion.  For a list of references, go to www.myriadpro.com/references.


Hereditary Pancreatic Cancer:

  • Pancreatic cancer patient with at least one close relative# with pancreatic cancer163-168
  • Individual with two or more close relatives# with pancreatic cancer
  • Individual of Ashkenazi Jewish descent with a personal history of pancreatic cancer or a first-degree relative# with pancreatic cancer*169-171
  • A previously identified PALB2 or BRCA2 mutation in the family172-178

#Close refers to first- or second-degree relatives. First-degree relatives include parents, siblings, children; second-degree relatives include grandparents, aunts/uncles, nieces/nephews
*Multisite 3 BRACAnalysis® may be the most appropriate initial test
 

^Assessment criteria based on scientific literature and expert opinion.  For a list of references, go to www.myriadpro.com/references


To help assess whether someone is a candidate for testing, they can take the Hereditary Cancer Quiz. This quiz can help them get the information they need to discuss with their risk of cancer with their healthcare provider and ask for further evaluation. If someone matches any of the red flags above or takes the quiz and finds red flags in their own history or their family history, they may benefit from hereditary cancer testing.

Hereditary cancer quiz

For more information about Myriad's Online Support Community, visit MySupport360:

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