In a case of Burkitt lymphoma, what is the most likely underlying abnormality of gene expression?

In Burkitt lymphoma, the most characteristic underlying abnormality in gene expression is the overexpression of the c-myc oncogene. This occurs due to a chromosomal translocation, typically t(8;14), which places the c-myc gene under the influence of strong immunoglobulin gene loci. This dysregulation leads to excessive production of the c-myc protein, which promotes cell proliferation and contributes to the malignancy.

The role of c-myc in promoting cell cycle progression and inhibiting differentiation makes it a key player in the pathogenesis of Burkitt lymphoma. By driving the expression of genes involved in growth and proliferation, c-myc contributes to the rapid cell division characteristic of this aggressive form of lymphoma.

In contrast, the other options represent genetic abnormalities that are not typically associated with Burkitt lymphoma. For example, while BCR-ABL is related to chronic myeloid leukemia and some acute leukemias, and loss of p53 is more commonly linked to various solid tumors, it does not play the central role in Burkitt lymphoma. BCL-2 overexpression is more often associated with follicular lymphoma and other types of non-Hodgkin lymphomas rather than Burkitt lymphoma itself