Microsatellites are short, repeated DNA sequences that exist throughou
t the genome. Instability of these sequences, associated with defects
in the DNA mismatch repair system, is the hallmark of hereditary non-p
olyposis colorectal cancer (HNPCC), and is also found in many sporadic
cancers. Although many types of solid tumors exhibit this type of gen
etic instability, its involvement in hematologic cancers is less evide
nt. We have investigated whether microstatellite instability (MSI) is
involved in the transformation of myeloid cells to myelodysplastic syn
drome (MDS) and/or acute myelogenous leukemia (AML). Both de novo and
treatment-associated neoplasias were studied. Only one example of MSI
was found in 48 patients, using a panel of 14 different microsatellite
loci consisting of repeats of one to four base pairs. These results s
uggest that the genes responsible for MSI are not involved in the tran
sformation of normal myeloid cells to MDS or AML. (C) Elsevier Science
, Inc., 1998.