microRNAs (miRNAs) are a recently discovered class of small non-coding RNAs that 
regulate gene expression. Rapidly accumulating evidence has revealed that miRNAs 
are associated with cancer. The human tissue kallikrein gene family is the 
largest contiguous family of proteases in the human genome, containing 15 genes. 
Many kallikreins have been reported as potential tumor markers. In this review, 
recent bioinformatics and experimental evidence is presented indicating that 
kallikreins are potential miRNA targets. The available experimental approaches 
to investigate these interactions and the potential diagnostic and therapeutic 
applications are also discussed. miRNAs represent a possible regulatory 
mechanism for controlling kallikrein expression at the post-transcriptional 
level. Many miRNAs were predicted to target kallikreins and a single miRNA can 
target more than one kallikrein. Recent evidence suggests that miRNAs can also 
exert 'quantitative' control of kallikreins by utilizing multiple targeting 
sites in the kallikrein mRNA. More research is needed to experimentally verify 
the in silico predictions and to investigate the possible role in tumor 
initiation and/or progression.