We have examined the position of the chromosomal breakpoint relative to the human c-myc gene (MYC) and the presence of other structural alterations of the same locus in 19 fresh samples of Burkitt lymphoma (BL) and 13 BL-derived cell lines.
Deregulated c-myc expression, as a consequence of translocation of the c-myc gene to one of the immunoglobulin loci, appears to play an important role in the pathogenesis of several B-cell tumors, including Burkitt's lymphoma, mouse plasmacytoma and rat immunocytoma.
We have analyzed the type of MYC/IG heavy-chain locus (IGH) rearrangement present in 15 patients affected by t(8;14)-positive primary Burkitt's lymphoma or acute lymphoblastic leukemia of the L3 type in an attempt to map in detail the locations of the chromosome 8 and chromosome 14 breakpoints.
In the Burkitt's lymphoma (BL) cell line BL67 the first exon of the c-myc gene is fused to the mu-switch region of the immunoglobulin heavy-chain gene (IgH).
Chromosomal translocations involving MYC at 8q24 are found in Burkitt lymphoma (BL), diffuse large B-cell lymphoma (DLBCL), and B-cell lymphoma, unclassifiable, with features intermediate between DLBCL and BL (BCLU).
We have determined the sequence of the normal human c-myc gene and compared it to portions of a c-myc gene that has been translocated into the immunoglobulin heavy chain locus in a Burkitt lymphoma cell.
We find that, during in vitro culture, Ramos mutates the c-MYC allele that is translocated into the IgH locus whilst leaving the untranslocated c-MYC and other control genes essentially unaffected.
We analyzed the Burkitt's lymphoma line BL64 in which a reciprocal translocation joins the immunoglobulin kappa light-chain locus on chromosome 2 to the c-myc gene on chromosome 8.
MYC gene alterations in diffuse large B-cell lymphomas and in B-cell lymphomas, unclassifiable, with features intermediate between diffuse large B-cell lymphoma and Burkitt lymphoma are frequently associated with BCL2 or/and BCL6 translocations conferring a very aggressive behavior.
The t(8;14)(q24;q32), involving MYC gene (8q24) and the immunoglobulin heavy chain (IgH) locus (14q32), represents about 75% of all translocations in Burkitt's lymphoma (BL).
MYC rearrangement is a recurring genetic abnormality in several aggressive B-cell lymphomas including: Burkitt lymphoma, diffuse large B-cell lymphoma; B-cell lymphoma, unclassifiable with features intermediate between diffuse large B-cell lymphoma and Burkitt lymphoma; rare de novo acute lymphoblastic lymphoma/leukemia, transformed follicular lymphoma, and plasmablastic lymphoma.
Constitutional activation of the MYC proto-oncogene resulting from a t(8;14) has been demonstrated in approximately 80% of Burkitt lymphoma patients, but only in one case of acute myeloid leukemia (AML).
Based on the clinical course and cytogenetic features of lymphoblasts in the bone marrow, which showed t(8;14) and c-myc gene rearrangement, the patient was diagnosed with Burkitt's lymphoma.
B-cell lymphomas with concurrent IGH-BCL2 and MYC rearrangements are aggressive neoplasms with clinical and pathologic features distinct from Burkitt lymphoma and diffuse large B-cell lymphoma.