MicroRNAs are involved in cancer-related processes. The microRNA-21(miR-21) has 
been identified as the only miRNA over-expressed in a wide variety of cancers, 
including cervical cancer. However, the function of miR-21 is unknown in 
cervical carcinomas. In this study, we found that the inhibition of miR-21 in 
HeLa cervical cancer cells caused profound suppression of cell proliferation, 
and up-regulated the expression of the tumor suppressor gene PDCD4. We also 
provide direct evidence that PDCD4-3'UTR is a functional target of miR-21 and 
that the 18bp putative target site can function as the sole regulatory element 
in HeLa cells. These results suggest that miR-21 may play an oncogenic role in 
the cellular processes of cervical cancer and may serve as a target for 
effective therapies.