MTREX and hepatocellular carcinoma: Considering that c-Myc is overexpressed in a majority of human cancers and promotes their tumorigenesis, but MTR4 is overexpressed in limited types of human cancers, we predict that c-Myc is necessary but not sufficient for activating the transcription of MTR4, and other HCC-specific transcriptional factors are required to collaborate with c-Myc in activating MTR4 transcription in HCC.