The frequent rearrangement of bcl-2 in a variety of B cell lymphomas of diffuse morphology (small cleaved cell, large cell, small noncleaved cell and immunoblastic) is noteworthy.
These data indicate that primary cutaneous lymphomas of B-cell origin share morphological and phenotypic similarities with the nodal B-cell lymphomas of follicular histotype, are proliferating, and express in 45% of cases clear monoclonal immunoglobulin light chain; the molecular analysis confirms the B-cell derivation and the monoclonal nature of this neoplasia; it also shows that neither bcl-2 nor c-myc oncogenes are involved and that no inappropriate rearrangements of the T-cell receptor genes are found in this lymphoma.
The human bcl-2 gene is a oncogene candidate which is involved in the t(14;18) translocation specifically associated with follicular and diffuse B cell lymphomas.
Antisense oligodeoxynucleotides specific for sequences in mRNAs from the B-cell lymphoma/leukemia-2 (BCL2) gene were used to inhibit the growth in culture of a human leukemia cell line, 697.
Moreover, the B-cell lymphomas were studied for the presence of the chromosomal translocations t(11;14) and t(14;18) using probes for bcl-1 and bcl-2 genes, respectively.
The putative oncogene bcl-2 is juxtaposed to the immunoglobulin heavy chain (Igh) locus by the t(14;18) chromosomal translocation typical of human follicular B-cell lymphomas.
Two of eight (25%) cases of follicular lymphoma but only one of the 34 (2.9%) cases of diffuse B-cell lymphoma had bcl-2 rearrangement that was detected by pFL-1 probe.
We conclude that abnormal expression of bcl-2 rather than structural alterations at codon 7 or 129 play an important role in the disordered growth and differentiation of follicular B-cell lymphoma.
To investigate the role of the BCL-2 gene in Japanese patients with B-cell non-Hodgkin's lymphoma, karyotypic analysis, DNA analysis and clinical characterization were studied.
Less involvement of bcl-2 in Japanese B cell lymphoma may also be in part explainable by low susceptibility to bcl-2 rearrangement at the step of DH-JH recombination.
Cases of NLPHD differ from most low-grade follicular B-cell lymphomas in that they lack bcl-2 gene rearrangement and t(14;18) translocation at the major breakpoint region.
The bcl-2 proto-oncogene, rearranged and deregulated in B-cell lymphomas bearing the t(14;18) translocation, encodes an inner mitochondrial membrane protein that blocks apoptotic cell death.