Gene Expression Profile Linked to Liver Cancer

The protein expression level of the transcription factor E2F5 can be estimated in formalin-fixed, paraffin-embedded tissue blocks by microarray technology. This transcription factor is encoded by the gene E2F5, which is part of a family that plays a crucial role in the control of cell cycle and action of tumor suppressor proteins and is also a target of the transforming proteins of small DNA tumor viruses.

Scientists at The Catholic University of Korea, (Seoul), analyzed 120 tissue samples from primary HCC patients and 29 normal liver tissues by immunohistochemistry (IHC) analysis. The E2F5-small interfering ribonucleic acid (RNA) was transfected into HepG2, an E2F5-overexpressed HCC cell line. They also explored the biological effects of E2F5 overexpression by knockdown of the gene and examined cell growth capacity and migrating potential. The investigators, using the tissue microarray-based IHC, found that E2F5 expression was mostly localized in the cytoplasm with occasional nuclear staining, and therefore cytoplasmic staining was considered a positive result. They found that 18.3% of the patients with HCCs were positive, while none of the normal liver tissues was positive.

The authors concluded that E2F5 is commonly overexpressed in primary human HCC and that E2F5 knockdown profoundly repressed the growth of HCC cells. The overexpression of E2F5 may induce uncontrollable cell cycle progression in liver cells and eventually contribute to cancer transformation by working together with other carcinogenic factors. This study will help to understand hepatocarcinogenesis mechanisms and to define therapeutic targets of early HCC. The study was published on January 28, 2011, in the World Journal of Gastroenterology.

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