Blastoid mantle cell lymphoma with t(2;8) (p12;q24)

The Role of c-MYC in B-Cell Lymphomas: Diagnostic and Molecular Aspects

c-MYC is one of the most essential transcriptional factors, regulating a diverse array of cellular functions, including proliferation, growth, and apoptosis. Dysregulation of c-MYC is essential in the pathogenesis of a number of B-cell lymphomas, but is rarely reported in T-cell lymphomas. c-MYC dysregulation induces lymphomagenesis by loss of the tight control of c-MYC expression, leading to overexpression of intact c-MYC protein, in contrast to the somatic mutations or fusion proteins seen in many other oncogenes. Dysregulation of c-MYC in B-cell lymphomas occurs either as a primary event in Burkitt lymphoma, or secondarily in aggressive lymphomas such as diffuse large B-cell lymphoma, plasmablastic lymphoma, mantle cell lymphoma, or double-hit lymphoma. Secondary c-MYC changes include gene translocation and gene amplification, occurring against a background of complex karyotype, and most often confer aggressive clinical behavior, as evidenced in the double-hit lymphomas. In low-grade B-cell lymphomas, acquisition of c-MYC rearrangement usually results in transformation into highly aggressive lymphomas, with some exceptions. In this review, we discuss the role that c-MYC plays in the pathogenesis of B-cell lymphomas, the molecular alterations that lead to c-MYC dysregulation, and their effect on prognosis and diagnosis in specific types of B-cell lymphoma.

Genomic profiling of mantle cell lymphoma

Genomic profiling of mantle cell lymphoma (MCL) cells has enabled a better understanding of the complex mechanisms underlying the pathogenesis of disease. Besides the t(11;14)(q13;q32) leading to cyclin D1 overexpression, MCL exhibits a characteristic pattern of DNA copy number aberrations that differs from those detected in other B-cell lymphomas. These genomic changes disrupt selected oncogenes and suppressor genes that are required for lymphoma development and progression, many of which are components of cell cycle, DNA damage response and repair, apoptosis, and cell-signaling pathways. Additionally, some of them may represent effective therapeutic targets. A number of genomic and molecular abnormalities have been correlated with the clinical outcome of patients with MCL and are considered prognostic factors. However, only a few genomic markers have been shown to predict the response to current or novel targeted therapies. One representative example is the high-level amplification of the BCL2 gene, which predicts a good response to pro-apoptotic BH3 mimetic drugs. In summary, genomic analyses have contributed to the substantial advances made in the comprehension of the pathogenesis of MCL, providing a solid basis for the identification of optimal therapeutic targets and for the design of new molecular therapies aiming to cure this fatal disease.