By genetically altering infected cells viruses prompt oncogenic transformation. Viruses alter the expression of microRNAs, non-coding RNA molecules that can block the expression of target genes finds several studies.
In this issue of the Journal of Clinical Investigation
, Xiaoje Xu and colleagues at the Beijing Institute of Biotechnology report that miR-148a is repressed by hepatitis B virus (HBV) X protein (HBx) to promote growth and metastasis of liver cancer. In normal liver cells, miR-148a represses the expression of the oncogenic protein HPIP, but the hepatitis B virus prevents expression of miR-148a, leading to increased levels of HPIP and subsequent oncogenic transformation. This study demonstrates that a cancer-associated virus promotes carcinogenesis through direct manipulation of a microRNA.