Distribution of BCL2 breakpoints in follicular lymphoma and correlation with clinical features: specific subtypes or same disease?
The t(14;18)(q32;q21) translocation is closely associated with follicular lymphoma (FL), and is routinely assessed with molecular methods exploring BCL2 breakpoints for both diagnosis and minimal residual disease (MRD) monitoring. We and others have previously reported new recurrent breakpoints (3'BCL2 and 5'mcr) which could be easily analyzed. In this study, we characterized the BCL2 breakpoints in 113 untreated patients with t(14;18)-positive FL and correlated their location with the location of JH break and with the clinical features. Breakpoints were respectively located at the major breakpoint region (MBR) in 73 cases (65%), at the minor cluster region (mcr) in 10 cases (9%), at 3'BCL2 in 14 cases (12%) and at 5'mcr in seven cases (6%). Finally, the breakpoint could not be located in nine patients (8%). 5'mcr cases were associated with bulky and high-stage disease, with frequent extranodal involvement and bone marrow infiltration. Survival studies did not show any correlation between breakpoint location and clinical outcome. The joining JH6 segment was the most frequently involved whatever the breakpoint location. In conclusion, unusual BCL2 breakpoints are found in about 20% of newly diagnosed follicular lymphomas and their study should be considered in the investigation of BCL2-JH rearrangement. It was not possible, in this series, to demonstrate any correlation between breakpoint location and either initial characteristics of the disease or survival of the patients.
INSERM, EMI 9906, IFRMP No. 23, Centre Henri Becquerel, Rouen, France.
G
G
Buchonnet
F
F
Jardin
N
N
Jean
P
P
Bertrand
F
F
Parmentier
S
S
Tison
S
S
Lepretre
N
N
Contentin
P
P
Lenain
A
A
Stamatoullas-Bastard
H
H
Tilly
C
C
Bastard
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002883:Chromosomes, Human, Pair 14 / Q000235:genetics*; D002887:Chromosomes, Human, Pair 18 / Q000235:genetics*; D017931:DNA Primers / Q000737:chemistry; D004273:DNA, Neoplasm / Q000032:analysis; D005260:Female; D006801:Humans; D007136:Immunoglobulins; D007621:Karyotyping; D008224:Lymphoma, Follicular / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D018365:Neoplasm, Residual / Q000235:genetics; D016133:Polymerase Chain Reaction; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000235:genetics*; D015996:Survival Rate; D014178:Translocation, Genetic
D017931:DNA Primers; D004273:DNA, Neoplasm; D007136:Immunoglobulins; D019253:Proto-Oncogene Proteins c-bcl-2