The proliferation of new techniques that allow a multiparametric study of gene expression, the mutational state of genomic DNA, DNA methylation and the phosphorylation of receptor and adaptor proteins has led to an increased understanding of the origin of different cancers, the definition of new prognosis markers and the response to treatment profiles. Gene profiling studies on chronic lymphocytic leukaemia (CLL) are at the origin of new prognosis markers such as zeta-associated protein-70 (ZAP-70), LPL and CLLU1, which, at present, are under study for their application to clinical practice. An increased resolution in the mutational state at genomic level has underscored the importance of deletion 13q14 at the origin of CLL and 13q and 17p in response to treatment. Some new insights regarding changes in gene expression in CLL cells depending on the microenvironment have been described, but more work is yet to be done in the field.