Known knowns
Identifying the known knowns is getting more complex. Panels of known
high penetrance cancer-causing genes are scrutinized by DNA sequencing
in individuals who qualify because of clinical and family history. For
each type of cancer there are different criteria, for instance for high
risk of hereditary breast-or-ovarian cancer or hereditary non-polyposis
colon cancer respectively. However, the set of cancers caused by each
mutated gene is
broader than
initially appreciated \cite{LaDuca_2019}, so it may be necessary to broaden the set of
clinical features used to justify testing, extend the set of genes on
the test panel, or include more individuals in familial testing. Still,
it is worth bearing in mind that prediction of the site of any future
cancer, or the outcome of an existing tumor becomes more difficult as
the complexity of the genetic test and its applications grow.