PAK4 and hepatocellular carcinoma: As the UPR transcription factor XBP-1 was identified as a target of miR-214 and recent studies have revealed the important functions of miR-199a/b-3p in HCC carcinogenesis and progression by targeting mTOR and c-Met or PAK4/Raf/MEK/ERK Pathway in HCC cells [5], [21], we decided to further investigate the correlation between UPR activation and miR-199a/214 down-expression.