V. Hjalmar et al., Sequential fluorescence in situ hybridization analyses for trisomy 12 in chronic leukemic B-cell disorders, HAEMATOLOG, 86(2), 2001, pp. 174-180
Background and Objectives. Trisomy 12 is one of the most common chromosomal
abnormalities in B-cell chronic lymptrocytic leukemia (CLL). The aberratio
n is readily detected by fluorescence in situ hybridization (FISH). There a
re only a few reports in which FISH analyses have been used to study the ex
pansion of the trisomy 12 clone over time.
Design and Methods. Repeat FISH analyses were performed in 77 patients with
a chronic leukemic B-cell disorder. The aim was to study the development o
f the trisomy 12 clone throughout the course of the-disease, to measure the
effect of therapy on the proportion of trisomic cells, and to relate the f
indings to the response to therapy.
Results. Fifty-eight of the 60 patients with no trisomy 12 at the initial t
est were consistently disomic for chromosome 12, while 2 patients seemingly
acquired trisomy 12 during folIow-up. Seventeen patients showed trisomy 12
at the first test. Expansion of the trisomy 12 clone was seen in all patie
nts with a progressive lymphocytosis. In contrast to poor responders, patie
nts responding well to chemotherapy showed a significant decrease in the pr
oportion of CD19(+) cells with trisomy 12. The effect of purine analogs in
patients with trisomy 12 seemed inferior, both clinically and when studying
the effect on the trisomic clone.
Interpretations and Conclusions. There is a strong association between expa
nsion of the trisomy 12 clone and progressive disease, both in treated and
untreated patients. Conversely, reduction of the trisomic B-cell clone was
linked to clinical response to chemotherapy. Acquisition of trisomy 12 rema
ins a rare event. (C) 2001, Ferrata Storti Foundation.