Chromosomal abnormalities and molecular genetics of non-Hodgkin's lymphoma

A number of recurring cytogenetic abnormalities have been identified in lymphomas that correlate with clinical, morphologic, and immunophenotypic features. For example, the t(14;18) is observed in a high proportion of follicular small cleaved cell lymphomas, most patients with translocations involving 3q27 have diffuse large cell lymphomas (B cell), and patients with a t(8;14) have either small noncleaved cell or diffuse large cell lymphomas. In contrast, a large proportion of neoplasms of T-cell origin are characterized by rearrangements that involve 14q11, 7q34-35, or 7p15. Molecular analysis of many of the recurring chromosomal translocations in lymphomas has resulted in the identification of the involved genes. Alterations in expression of these genes or in the production of an altered protein resulting from the rearrangement play an integral role in malignant transformation. In addition to chromosomal abnormalities, other types of mutations affecting oncogenes have been identified in lymphomas. This article reviews the genetic mutations involved in the pathogenesis of non-Hodgkin's lymphoma (NHL) with an emphasis on chromosomal abnormalities.