NCCN Guidelines for Patients
Acute Lymphoblastic Leukemia, Version 1.2017
Testing for ALL
Doctors use FISH to detect certain abnormal gene
and chromosome changes in leukemia cells. This
test uses special color dyes, called probes, that
attach only to certain genes or parts of certain
For example, the Philadelphia chromosome is a
common abnormal change found in adults with ALL.
This chromosome contains the
gene. To detect this, FISH uses color probes that
attach to the
gene and the
fusion gene is shown by the overlapping
colors of the two probes.
Like cytogenetic testing, FISH is used to help plan
and monitor treatment for ALL. This test can be
performed on a sample of blood or bone marrow.
eaction) is a very sensitive
test. Like FISH, it detects abnormal gene and
chromosome changes (mutations) in cells. However,
it can find mutations that are too small to be seen
with a microscope.
Doctors use this test to detect certain gene and
chromosome changes that are commonly found in
ALL. An example of this is the
This gene is found on the Philadelphia chromosome.
PCR can detect gene mutations and measure the
number of cells that have them.
PCR is very helpful for checking how well treatment
is working. When the cells have certain genetic
changes, PCR can find and measure the amount of
leukemia cells left. This test can find one leukemia
cell among more than 10,000 normal cells. PCR
is the method used to find the amount of disease
present after treatment. Doctors use this to assess
for MRD (
isease). The presence of
MRD is a key factor used to decide if more treatment
is needed. (See page 37 for more details about
checking treatment results.)
PCR can be done on a sample of bone marrow
or blood. But, bone marrow is often preferred,
especially when checking treatment results.