Since 2000, we have investigated 67 consecutive patients with stage I/II follicular lymphoma (FL) for the presence of BCL2/IGH rearrangements by polymerase chain reaction (PCR), real time quantitative PCR (RQ-PCR) and digital droplet PCR (ddPCR).
Although the majority of patients with follicular lymphoma (FL) harbor the t(14;18)(q32;q21)IGH/BCL2 gene rearrangement that leads to the overexpression of BCL2 protein, approximately 20% of FL cases lack t(14;18)(q32;q21).
Cytogenetic analysis and targeted next-generation sequencing of both FL and HS tumors identified common genomic alterations such as IGH-BCL2 rearrangement, CREBBP and KMT2D, and aberrations of chromosomes 9q and 19q.
Fluorescence in situ hybridization (FISH) identified an IGH-BCL2 rearrangement in both the FL and high-grade B-cell components while a MYC rearrangement was detected in the high-grade B-cell component alone.
Comparative analysis between RQ-PCR and digital droplet PCR of BCL2/IGH gene rearrangement in the peripheral blood and bone marrow of early stage follicular lymphoma.
The FL with signet-ring cell morphology (1/5) tends to lack IGH/BCL2 translocation, and an extended immunohistochemical study is recommended for correct diagnosis and classification of SRCL.
Follicular lymphoma (FL) is characterized genetically by a significant intraclonal diversity of rearranged immunoglobulin heavy chain (IGH) genes and a substantial cell migration activity (follicular trafficking).
Of these, t(14;18)(q32;q21) results in juxtaposition of the IGH gene on chromosome 14 and the BCL2 gene on chromosome 18, leading to the overexpression of BCL2 anti-apoptotic protein, which plays a critical role in the development of follicular lymphoma (FL).
Intraclonal heterogeneity in follicular lymphoma (FL) is apparent from studies of somatic hypermutation (SHM) caused by activation-induced deaminase (AID) in IGH.
In the present study, 5/6 cases in which FISH was successful had an IGH/BCL2 fusion as would result from the t(14; 18)(q32; q21) translocation commonly seen in FL of extraoral sites.
This study aimed to determine the correlations of 7 histopathologic prognostic indicators of follicular lymphoma (follicular lymphoma grade, CD10 expression, Bcl-2 expression, IGH/BCL2 fusion, diffuse area, fibrosis, and marginal zone differentiation) with progression-free survival, overall survival, and follicular lymphoma histologic grade in 255 follicular lymphoma patients who were treated with rituximab-containing therapy.
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.
In the first case, the FLwas negative for IGH-BCL2 and harbored a novel IGH-associated translocation; in the second case, the CL manifested in the skin.
In conclusion, pretreatment quantity of BCL2/IGH in PB or BM seems to mirror the extent of disease and can provide an auxiliary prognostic parameter in FL.
The most common genetic aberration in follicular lymphoma (FL) is the t(14;18)(q32;q21) translocation that juxtaposes the antiapoptotic BCL2 gene with the promoter of the immunoglobulin heavy-chain (IgH) gene, which is the molecular hallmark of FL, whereas a subset of cases harbor translocations involving the BCL6 gene locus.
Molecular diagnostic laboratories face such difficulties with the BCL2-IGH translocation in follicular lymphoma and with internal tandem duplication mutation of the FLT3 gene in leukemia, where breakpoints are widely distributed, mutations may be multiple, signal strength is low, and background noise is elevated.
The sequence analysis of the IgH gene revealed both of cells originated from the same clone, showing that the aggressive BL-like tumor originated from the FL-like clones simultaneously found in the bone marrow.
Demonstration of array-based analysis for highly multiplexed PCR assays application to detection of IGH@-BCL2 translocations in FFPE follicular lymphoma specimens.