White cells 2: impact of understanding the molecular basis of haematological malignant disorders on clinical practice.

The molecular basis of many leukaemias is now known, allowing precise diagnosis. Treatment of chronic myeloid leukaemia is now possible by targeting of the BCR-ABL tyrosine kinase. The underlying molecular abnormalities in acute leukaemias allow the outlook for individual patients to be assessed at diagnosis and therapy tailored accordingly. Analysis of V(H) genes in B-cell malignant disorders allows these to be placed in the hierarchy of B-cell development and may provide prognostically valuable information.