CORRELATION OF TRISOMY-12 WITH PROLIFERATING CELLS BY COMBINED IMMUNOCYTOCHEMISTRY AND FLUORESCENCE IN-SITU HYBRIDIZATION IN CHRONIC LYMPHOCYTIC-LEUKEMIA
Ja. Garciamarco et al., CORRELATION OF TRISOMY-12 WITH PROLIFERATING CELLS BY COMBINED IMMUNOCYTOCHEMISTRY AND FLUORESCENCE IN-SITU HYBRIDIZATION IN CHRONIC LYMPHOCYTIC-LEUKEMIA, Leukemia, 10(11), 1996, pp. 1705-1711
Conventional G-banding and fluorescence in situ hybridization (FISH) w
ere performed on peripheral blood samples of 340 consecutive untreated
cases of chronic lymphocytic leukemia (CLL) for the detection of tris
omy 12 and other chromosome abnormalities. These findings were correla
ted with the proliferative activity of CLL lymphocytes assessed by the
monoclonal antibody Ki-67. Cytogenetic analysis displayed a normal ka
ryotype in 131 (38.5%) cases, trisomy 12 in 68 (20%), 31 by G-banding
and an additional 37 cases by FISH, other clonal abnormalities in 47 (
14%), and no metaphases in 94 (27.5%). The percentage of Ki-67-positiv
e cells was significantly higher in cases with trisomy 12 (4.1 +/- 4.4
8) than in cases with a normal karyotype (1.5 +/- 2.0), those with oth
er clonal abnormalities (1.35 +/- 1.37) and cases with no metaphases (
1.14 +/- 1.6) (P < 0.0001). Cases with trisomy 12 were associated with
more advanced clinical stage, atypical morphology and a higher percen
tage of Ki-67+ve cells than cases lacking trisomy 12 (P < 0.0001). Alt
hough there was no direct correlation between the percentage of trisom
ic and proliferating cells, the combination of immunocytochemistry and
FISH showed that most Ki-67-positive cells were trisomic for chromoso
me 12. Our results suggest that the association of trisomy 12 with a h
igher proliferative activity supports the view that this abnormality i
s a secondary event associated with disease progression in CLL.