45
percent
32– 42
percent
average U.s. man’s
lifetime risk of any
cancer
estimated cancer risk for a man
following a negative genomic
screen for cancer
DNA flunks disease predicting test
genetic blueprint can foretell risk for only a few disorders
By Tina Hesman Saey
The human genetic instruction book is
as lousy at predicting disease as an almanac is at predicting the weather, a prominent cancer researcher concludes based
on data from identical twins.
Deciphering the genetic books, called
genomes, is quicker and cheaper than
ever. Scientists have touted the genome
as a crystal ball for peering into people’s
medical futures. But Bert Vogelstein
of Johns Hopkins University School of
Medicine wondered just how informative a person’s genetic makeup could be.
So Vogelstein and colleagues gathered
medical data from 53,666 t win pairs from
around the world. Identical twins share
their genetic makeup, so looking at one
twin’s health history may reveal what
medical complications the other twin’s
genome can foretell. The researchers did
not decipher the t wins’ genomes but used
the medical data to develop a mathematical formula to predict the minimum and
maximum risk of getting 24 different
diseases, including several cancers, heart
disease, diabetes and Alzheimer’s.
For all but four diseases, the genetic
data would fail to determine who is likely
to contract the condition in most cases,
Vogelstein reported April 2. The results
were also published online April 2 in
Cancer fate tied to protein location
an old real estate axiom may also be a
key to pancreatic cancer patients’ fate.
the location of a protein called sur-
vivin may influence whether pancreatic
cancer cells are susceptible to chemo-
therapy after surgery, researchers led
by Barbara Burtness of Fox chase
cancer center in Philadelphia reported
april 1. Patients whose tumor cells
harbored survivin in the nucleus lived
longer without a recurrence of cancer
than patients whose tumor cells con-
tained the protein outside the nucleus.
no difference was detected between
the two groups after surgery alone, but
surgery followed by radiation or chemo-
therapy kept tumors with survivin in
the nucleus in check longer. the result
supports previous research indicating
that survivin’s location can make cancer
cells more or less vulnerable to chemo-
therapy. — Tina Hesman Saey
