In conclusion, the majority of Bcl-2-negative FL lack a t(14;18) but a significant subset of these tumours are false negative due to mutations in the BCL2 gene.
The use of three distinct anti-bcl-2 antibodies together with CD10 expression data and FISH analysis for bcl-2 and bcl-6 rearrangements allowed subclassification of follicular lymphoma into four distinct subgroups: (i) CD10-positive/bcl-2-positive, (ii) CD10-positive/bcl-2-negative, (iii) CD10-negative/bcl-2-positive, and (iv) CD10-negative/bcl-2-negative.All cases were bcl-6-positive.
In Taiwan, FL3A tumours were more closely related to FL3B tumours than to LG tumours, and a literature review showed that the frequency of t(14;18)/IGH-BCL2 in FL in Taiwan is among the lowest in the world.
We report the use of the polymerase chain reaction (PCR) technique for detecting and sequencing clonal bcl-2/JH rearrangements in lymph nodes and/or bone marrow specimens from patients with follicular lymphoma.
Since the discovery of bcl-2 proto-oncogene in follicular lymphomas, the protein product has been detected in a variety of normal tissues including skin, where it is expressed in basal keratinocytes.
Only 1 non-exposed individual was positive for the chromosomal translocation, and healthy radio-exposed individuals presented lower levels of cells bearing the BCL2/J(H) rearrangement when compared to the levels of the patients with follicular lymphoma before treatment.
Follicular lymphoma is characterized by the presence of the t(14;18)(q32;q21) chromosomal translocation that juxtaposes the bcl-2 gene at 18q21 with the immunoglobulin heavy chain (IgH) locus at 14q32.
Sequence analysis showed the amplified bcl-2/JH fragments to be unique to each individual sample and distinct from 24 sequenced follicular lymphoma-derived t(14;18) junctions, thus excluding contamination artifacts.
These data indicate 2 distinct types of follicular lymphomas presenting in the ovary: a low-grade/high-stage/BCL2-positive group and a higher-grade/low-stage/BCL2-negative group.
To determine the relative importance of these mutations, we searched for their presence in DNA from the involved lymph nodes of 12 patients with t(14; 18) follicular lymphoma. bcl-2 genomic sequences were specifically amplified by the polymerase chain reaction technique and then directly sequenced.
Early data from the tazemetostat trials indicate an acceptable safety profile and early signs of activity in diffuse large B-cell lymphoma and follicular lymphoma, including patients with EZH2 wild-type and mutant tumors.