Expression data from CLL patient samples investigated to define biologic heterogeneity.

Chronic lymphocytic leukemia shows a variable clinical course which is associated with distinct alterations such as chromosomal aberrations, gene mutations or IGHV mutation status. Refining biologic categories may help to improve clinical management with available and future treatment approaches. We used Affymetrix Exon 1.0 ST microarrays to investigate differences in CLL biology. Gene expression profiling on samples from CLL patients was conducted by using CD19 sorted and unsorted peripheral blood mononuclear cells from patients treated on randomized international CLL trials using chemo or chemoimmunotherapy.