Gastrointestinal stromal tumors (GIST)

A gastrointestinal stromal tumor (GIST)
is a type of tumor that occurs in the
gastrointestinal (GI or digestive) tract,
including the esophagus, stomach,
gallbladder, liver, small intestine,
colon, and rectum. GIST is different
from other types of gastrointestinal
tumors because of the type of tissues
in which it starts. Originally, GISTs
were thought to be either muscle or
nerve tumors, but recent research
points to GISTs starting in cells found
in the walls of the GI tract, called
interstitial cells of Cajal (ICC); these
cells send signals to the GI tract to
help move food and liquid through the
system.


HERCEPTIN TEST APPROVED FOR
STOMACH CANCER
FDA approved  the Danish company
Dako's  HercepTest  and HER2 FISH
pharmDx  Kit  for identification of
patients with metastatic stomach
cancer who are appropriate for HER2
targeted therapy with Herceptin.

The diagnostic tests can identify the
group of patients  having  
HER2-positive metastatic gastric or
gastroesophageal junction
adenocarcinoma, and  are appropriate
candidates for receiving the right
combination of targeted treatment and
chemotherapy.
These diagnostic kits will   aid in the
selection the approx. 22% of the
estimated 21,130 Americans who are
diagnosed with stomach  cancer each
year.

The FDA approval was  based on the
positive results of an  international
Phase III study (ToGA).
It involved 3,700 patients at 122 sites
in 24 countries.

The treatment with Herceptin in
combination with chemotherapy in
patients  with metastatic HER2-positive
stomach cancer found by the use
of Dako's diagnostic tests significantly
prolonged the lives of patients with this
aggressive cancer.



GLIVEC TO BE USED FOR GIST IF
CELLS HAVE CD117 RECEPTOR
Glivec (imatinib) is often used to treat
GIST that can't be completely removed
with surgery. Glivec is a type of
biological therapy called a tyrosine
kinase inhibitor. This means it blocks a
an enzyme that the cancer needs in
order to grow.
The surgeon removes a sample of the
tumor during the operation and sends
it to the laboratory. A specialist tests
the cells to confirm the diagnosis of
GIST, and to see if the cells have a
receptor on their surface called
CD117. If the cells are CD117 positive,
Glivec is likely to work very well. But it
can work even for GISTs that are
CD117 negative.
An American trial  found that for 98 out
of 100 people (98%) taking Glivec, the
GIST stayed under control for at least
1 year, compared to 83 out of 100
people (83%) for those not taking
Glivec.


TASIGNA  TESTED FOR  GIST
An international trial is comparing a
new type of biological therapy called
nilotinib (Tasigna) with imatinib for
gastrointestinal stromal tumors that
cannot be completely removed with
surgery, or have spread to other parts
of the body. The trial aims to find out if
nilotinib helps people with a GIST more
than imatinib.



OTHER DEVELOPMENTS
SUTENT
A drug, called sunitinib (or Sutent)  
from Pfizer was recently licensed in
Europe to treat GIST if Glivec does not
work, or stops working.