precursors, i.e., monoclonal B cell lymphocytosis (MBL) for CLL and myelodysplastic syndrome for acute myelogenous leukemia. Recent work shows that the majority of MBL have mono- or biallelic 13q14 abnormalities21. However, further studies will be needed, preferably with serial pre- and post- diagnosis sampling to investigate the predictive nature of detectable clonal mosaicism, especially involving regions of chromosome 13 and 20 with respect to leukemia risk20.
