The molecular background of aggressive B cell lymphomas as a basis for targeted therapy.

In contrast to classifications for the majority of solid tumours, non-Hodgkin's lymphomas have been defined on the basis of their genetic alterations for many years, providing a biologically highly relevant classification. However, for aggressive B cell lymphomas, which unfortunately is the most prevalent group of lymphomas in adults, the stratification is less optimal. Gene expression profiling, analyses of chromosomal alterations and functional assays have been instrumental in dissecting these tumours to support the distinction of essentially different diseases, such as diffuse large B cell lymphoma and Burkitt's lymphoma, and now start to identify the dominant driving oncogenetic pathways that may serve as rational therapeutic targets in this essentially heterogeneous group. In this review, the molecular background and the consequences of the molecular alterations in the context of the consequences for treatment in aggressive B cell lymphoma are discussed.