Researchers must show that the drug
predictions that seem so promising in a dish actually work in patients.
They also will need to deal with technological issues, such as the time
it takes to grow patients’ tumor cells in a dish, between two and six
months in the study, and not every attempt was successful.
“For
decades, literally decades, people have wanted to do patient-specific
chemotherapy sensitivity testing, and it’s been a very hard problem,”
said Dr. James Eshleman, a professor of pathology and oncology at Johns
Hopkins University School of Medicine, who was not involved in the work.
“One problem which is totally counterintuitive is that cancers grow in
patients just fine, but” in a dish, “it’s relatively hard to generate
cell lines, and specific cancers are extraordinarily difficult, largely
for reasons that we don’t understand.”
The
researchers believe that with time, those technological issues can be
resolved. The study used an imperfect source of cells, leftovers taken
from biopsies that had been done for other purposes. If the biopsies
were taken with the idea of growing cells and testing drugs, it is
likely that the process could be quicker and more efficient.
A
far bigger question looms: Sometimes, therapies that seem like a home
run in laboratory tests or even animal models of cancer do not work in
people.
“This is really setting up the
criteria for what we have to look at next,” Schlegel said. “Someone has
to figure out if we grow up these cells, how many times is this going to
be an adequate predictor of patient response?”
Engelman said he already is beginning to work on the answer to that question.
His
team will start by reexamining clinical trials in which patients
received drugs and their responses were known. Researchers will then
grow cells harvested from their tumors in a dish to see whether the
people who had the best responses to the drug also happened to have
cells that were more sensitive to the treatment, as researchers would
expect.
If that work shows promise, it will help provide the evidence needed to begin using the tool to guide cancer care in patients.
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