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Race and Cancer Genetics: Lessons From BRCA1

Race and Cancer Genetics: Lessons From BRCA1

Health disparities among populations within the United
States are well documented. In order to eliminate these disparities, we must
further understand their sources. Are they the result of the unequal
distribution of resources, racism, or inherent characteristics of ethnically or
"racially" defined groups? How we define and discuss "race"
has major scientific and moral consequences. In this issue, Leslie Klein Hoffman
asks two major questions as they pertain to research on ethnic or
"racially" defined groups. When is genetic research on a population
appropriate? How should researchers define a given population? These questions
are timely, and it is both humbling and instructive that the answers to these
questions remain unclear.

Ms. Hoffman’s questions are important for two reasons. First, with its
recent Health Disparities Initiative, the US government adopted the goal of
eliminating health inequality among racially and ethnically defined populations
by the year 2010.[1] Second, the completion of sequencing the human genome and
the intersection of genomics and medicine has the potential to transform all
areas of medicine from the etiology, prevention, diagnosis, and treatment of
diseases to the development of designer drugs (pharmacogenomics). How we act on
the answers to Ms. Hoffman’s questions will either help bring about the
changes needed to transform medicine and eliminate health inequalities, or it
will strengthen the reification of "race" and "racialized"
diseases.

Racialized Diseases

Ms. Hoffman presents issues related to terminology and genetic literacy that
exemplify the consequences of associating a disease with an identifiable
population (ie, racialized diseases). When one considers breast cancer and BRCA1
and BRCA2 mutations, thoughts of Ashkenazi Jews are evoked. The association of
BRCA1 and BRCA2 mutations with the Ashkenazi population was an unintended
consequence of research designs and the translation of results to the general
public. The favored research design had the advantage of finding the mutations
among a relatively genetically homogeneous population—Ashkenazi Jews—which
was possible due to a founder’s effect, and the hereditary mutations were
found by ascertaining probands with a positive family history and then family
members.

The results illustrate that the susceptibility alleles were segregating in
some high-risk families, which denotes lineages and not "racial"
genotypes. Breast cancer susceptibility alleles are not specific to Ashkenazi
Jews, and Ms. Hoffman shows that despite the good intentions of the researchers,
there were some negative outcomes that should be addressed.

Research in Specific Populations

Why should we perform cancer genetics research within specific identifiable
populations? The answer is quite simple. Some populations may be more
informative because of a higher prevalence and the higher risk of relatives of
affected individuals. Also, genetic consequences of the history of certain
populations may make them advantageous for finding susceptibility genes.[2] When
is genetic research on a population appropriate? This varies, but one can
justify doing cancer genetic research in populations where there is an increased
incidence, progression, and/or mortality suggestive of a strong genetic
contribution.

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