The Wilms' tumor protein, WT1, represses transcription from several growth
factor genes. WT1 transcription is regulated in erythroid and myeloid linea
ges by the transcription factor GATA-1. Using a sensitive, isotopic duplex
RT-PCR procedure amplifying WT1 or GATA-1 together with beta-actin as the i
nternal control in a single reaction mix, we quantitated the expression of
WT1 and GATA-1 mRNA of 16 patients with myelodysplastic syndrome (MDS), 56
with acute myeloid leukemia (AML) and 22 with acute lymphoblastic leukemia
(ALL). K562 was used as reference positive control for this cell line expre
sses both WT1 and GATA-1. Among MDS patients, increased WT1 expression was
found in refractory anemia with excess blast (RAEB) and RAEB in transformat
ion (RAEB-T) subtypes compared to the normal controls, whereas WT1 expressi
on in refractory anemia (RA) was not different from the normal control leve
l. All of AML cases of subtypes M0, M1, M2 and M3 expressed WT1 more than t
hree times the normal WT1 level. Subtypes M4 to M7 showed significantly low
er WT1 levels than M1 to M3 and AML cases with CD14(+) expressed less WT1 t
han CD14(-). Higher than normal WT1 levels were also expressed in cases of
ALL.