BACKGROUND/AIMS: The degradation of mRNA is a key process in the control of gene 
expression correlated to anomalous cell proliferation. The rate-limiting step of 
mRNA degradation is the removal of the poly(A) tail by deadenylases. However, 
studies on deadenylase expression in cancer are limited. Herein, we analyzed the 
expression of several deadenylases from acute lymphoblastic leukemia (ALL) and 
acute myeloid leukemia (AML).
METHODS: Clinical samples from patients diagnosed with ALL and AML were the 
source of leukemic cells. Extracts from leukemic and control cells were analyzed 
for deadenylase mRNA levels using qRT-PCR, and the protein levels of PARN and 
CNOT7 deadenylases using immunoblotting.
RESULTS: RT-PCR analysis revealed altered expression for CNOT6, CNOT6L, CNOT7 
and PARN deadenylases. The most significant alterations were observed for PARN 
and CNOT7 mRNA levels, which also reflect on the cognate protein level. Further 
analysis revealed that a significant amount of PARN is phosphorylated in ALL.
CONCLUSIONS: We show that the expression of several deadenylases in acute 
leukemias is altered. The increase of PARN expression and the alteration of its 
phosphorylation status indicate important regulatory events. These data suggest 
that the role of deadenylases as auxiliary biomarkers and therapeutic targets 
should be meticulously investigated.