Family History Discussion
[Slide 36] Ask students to compare their responses to Steve's questions with those of
the genetic counselor, Ms. Smith. Go over the important information in a family
pedigree needed in order to begin an analysis of a family's cancer risk:
o History of cancer in the family and number of generations affected (If cancer
is found in every generation, there is a greater possibility that a genetic
mutation is present.)
o Types of cancer present (Certain genetic mutations are associated with more
than one type of cancer. For example, BRCA2 mutations cause increased risk
of breast and ovarian cancer in women and breast and prostate cancer in
males. Therefore, if these types of cancer are present in one family, there may
be a BRCA mutation present.)
o Age of cancer diagnosis (Since the main risk factor for cancer is age, a
diagnosis of cancer before age 50 strongly suggests there may be an
inherited genetic mutation present.)
o Multiple cancers in one generation
o Other causes of death
o Current age or age of death
Note to students that not all cases of breast cancer are caused by an inherited
mutation; only 5–10 percent of breast cancer is inherited. Most cancer may be the
result of environmental exposures, or a combination of both genetic and
environmental factors.
Group Discussion and Activity: Williams Family Pedigree
[Slides 37–38] Explain to students that they will use the family history information
that Nikki found to complete a pedigree of the Williams family.
[Slide 39] Learning Activity: Discussion. Distribute copies of the Incomplete Williams
Family Pedigree and ask students to fill in the missing information in small groups or
as a class. As a class, discuss relevant information from the incomplete Williams
Family Pedigree worksheet, including the following:
o History of cancer in the family and number of generations affected (If cancer
is found in every generation, there is a greater possibility that a genetic
mutation is present.)
o Types of cancer present (Certain genetic mutations are associated with more
than one type of cancer. For example, BRCA2 mutations cause increased risk
of breast and ovarian cancer in women and breast and prostate cancer in
males. Therefore, if these types of cancer are present in one family, there may
be a BRCA mutation present.)
o Age of cancer diagnosis (Since the main risk factor for cancer is age, a
diagnosis of cancer before age 50 strongly suggests there may be an
inherited genetic mutation present.)
o Multiple cancers in one generation
o Other causes of death
o Current age or age of death