Epigenetics of hepatocellular carcinoma: a new horizon / 中华医学杂志(英文版)

Epigenetic changes refer to stable alterations in gene expression with no underlying modifications in the genetic sequence itself. It has become clear that not only gene variations but also epigenetic modifications may contribute to varied diseases, including cancer. This review will provide an overview of how epigenetic factors, including genomic DNA methylation, histone modifications, and miRNA regulation, contribute to hepatocellular carcinoma (HCC) dissemination, invasion, and metastasis. Additionally, the reversal of dysregulated epigenetic changes has emerged as a potential strategy for the treatment of HCC, and we will summarize the latest epigenetic therapies for HCC.

Demethylation of the gamma-synuclein gene CpG island in colorectal cancer and its clinical significance / 中华胃肠外科杂志

<p><b>OBJECTIVE</b>To explore the relationship between gamma-synuclein gene expression and CpG island demethylation in colorectal cancer(CRC), and the relationship between the demethylation and clinicopathological factors of CRC.</p><p><b>METHODS</b>The expression of gamma-synuclein mRNA was examined in 30 pairs of tumor tissues and tumor-matched non-neoplastic adjacent tissues(NNAT) by RT-PCR. CRC cell lines including COLO205, LoVo, and SW480 were used and treated with a demethylating agent, 5-aza-2'-deoxycytidine(5-aza-C). Before and after the treatment, the expression of gamma-synuclein mRNA in the cells was determined by RT-PCR, and bisulfite sequencing PCR was also used to analyze methylation status of CpG island. The methylation status of gamma-synuclein was then examined in 67 CRC samples and 30 NNAT samples by nested methylation-specific PCR (NMSP) and real time methylation-specific PCR(real-time MSP). The relationship between the demethylation of gamma-synuclein in CRC and clinicopathological factors was analyzed.</p><p><b>RESULTS</b>The mean gamma-synuclein mRNA expression was 0.66+/-0.34 in CRC samples, which was much higher than 0.45+/-0.26 in NNAT samples(P=0.011). 5-aza-C could induce expression and demethylation of gamma-synuclein in COLO205, LoVo and SW480 cells. gamma-Synuclein gene was demethylated in 80.0%(24/30) of the CRC samples and 50.0%(15/30) of the NNAT samples. The demethylated status of gamma-synuclein was much higher in CRC samples than that in NNAT samples(P=0.030), and was significantly correlated with clinical stage, lymph node involvement, and distant metastasis of CRC(P<0.05).</p><p><b>CONCLUSION</b>The upregulation of gamma-synuclein expression in CRC is primarily attributed to the demethylation of CpG island, which may be used as a marker for prognosis.</p>