0:00
My name is Susana Raimondi.
I work at St. Jude
Children's Research Hospital.
I'm the director of the
Cytogenetics Laboratory,
and the presentation today
will be about the cytogenetics
of childhood acute leukemias.
0:17
Regarding the topic today,
the molecular changes
occur at the chromosome level, at
the gene level, or DNA sequences.
A full range of
genetic abnormalities
is indicative of cancer, but many
of the chromosomal alterations
observed by conventional
cytogenetics
alone do not induce leukemia.
Sometimes, there are no obvious
chromosomal alterations.
And some microscopic
genetics alterations may be
of leukemogenic/actionable events.
0:54
Regarding the cytogenetics of
acute lymphoblastic leukemia,
1:00
when we consider the pediatric
population, about 15% of the cases
are T-lineage.
They do have recurring
chromosomal aberrations.
However, they do not have
impact on the clinical behavior
of these patients with
T-lymphoblastic leukemia.
There's others that
have B-lineage leukemia.
About 50% of the cases have either
hyperdiploid with greater than 50
chromosomes, or a translocation that
is cryptic that is called t 12;21.
The other subsets are smaller.
And some of them are
strongly associated
with very poor prognosis.
1:50
The genetic classifications.
We work with favorable
prognoses and adverse prognoses.
Favorable prognoses
are the translocation
12;21 and the hyperdiploid
with 51 to 67 chromosomes.
Adverse prognosis is
subclassification,
subgroup of early
T-cell precursor ETP,
which is diagnosed
by flow cytometry.
And I will not further
explain that subgroup.
Other subgroup, a small
one, is the amplification
of ABL1 with a NUP214 on the 9q.
And that is observed in T-cells
ALLs associated with a poor outcome.
The translocation 9;22
BCR-ABL has improved
prognosis with ABL inhibitors.
11 q23 aberrations of MLL gene have
very poor prognosis, especially
in infants less than six months and
with a high white blood cell count.
Hyperdiploidy with less
than 44 chromosomes,
the amplification of
a gene on 21q RUNX1,
and the translocation
1;19 also associated
with a higher risk of CNS relapse.
And in the recent years, there are
a lot of new molecular markers.
