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0:00
I'm Professor Charis Eng, the Hardis
chairperson of the Genomic Medicine
Institute and director at the
Center for Personalized Genetic
Healthcare at the Cleveland Clinic.
I shall be speaking to you about
the PTEN Hamartoma-tumour Syndrome
as a model for the practice
of clinical cancer genetics.
0:21
When we practice
clinical cancer genetics,
we ask ourselves when faced
with a patient with cancer,
is it heritable or is
it sporadic?, because this
has implications for the patient.
For example, which cancers will
this patient be at risk for?
At what ages do these risks arise?
What does one do for the patient?
In addition to the patient,
what are implications
for the patient's family?
Who amongst them is
at risk for cancer,
and what does one do for
each family member at risk?
0:56
Clinical clues suggesting heritable
cancer include young age of onset,
bilateral disease in paired organs,
multifocal tumors, association
with other tumor types-- for
example, breast and ovarian
cancer, colon and
endometrial cancers.
Familial clustering of
cancers, but not always.
1:21
Clinical cancer genetics
in 2013 can be powerful.
When presented with a patient
with cancer, in this illustration
of breast cancer we ask, is
it hereditary or sporadic?
Epidemiologic studies tell
us that 10% to 15% on average
are caused by high
penetrance mutant genes.
But which 10% to 15%?
By looking at personal and family
history details such as age
at onset, presence of other types
of cancer, affecting one or more
organs, and family
history using pedigrees,
one can determine
whether one is low-risk
when none of these hallmarks are
present or high-risk if one or more
are present.
If the patient is high risk,
pretest genetic counseling
is offered and the
specific gene test as well.
When the gene test
results are ready,
the patient will receive
the results in the setting
of post-test counselling.
If the test is positive, then
gene informed risk management
surveillance and prophylaxis
may be instituted.
Should none of the clinical
hallmarks of heritable cancer
are present, the patient
is said to be low risk
and the national guidelines for
the national population instituted.
