[HTML][HTML] Decreased 5-hydroxymethylcytosine levels correlate with cancer progression and poor survival: a systematic review and meta-analysis

Z Chen, X Shi, L Guo, Y Li, M Luo, J He - Oncotarget, 2017 - ncbi.nlm.nih.gov
Z Chen, X Shi, L Guo, Y Li, M Luo, J He
Oncotarget, 2017ncbi.nlm.nih.gov
Ten-eleven translocation (TET) enzymes catalyze the oxidation of 5-methylcytosine (5-mC)
to 5-hydroxymethylcytosine (5-hmC) and then to 5-formylcytosine (5-fC) and 5-
carboxylcytosine (5-caC), resulting in genomic DNA demethylation. Decreased 5-hmC
levels have been reported in a variety of cancers, and loss of 5-hmC might be considered an
epigenetic hallmark of cancer. However, the prognostic value of decreased 5-hmC in
cancers remain controversial. Here, a systematic review was performed by conducting an …
Abstract
Ten-eleven translocation (TET) enzymes catalyze the oxidation of 5-methylcytosine (5-mC) to 5-hydroxymethylcytosine (5-hmC) and then to 5-formylcytosine (5-fC) and 5-carboxylcytosine (5-caC), resulting in genomic DNA demethylation. Decreased 5-hmC levels have been reported in a variety of cancers, and loss of 5-hmC might be considered an epigenetic hallmark of cancer. However, the prognostic value of decreased 5-hmC in cancers remain controversial. Here, a systematic review was performed by conducting an electronic search of PubMed, EMBASE, Web of Science and the Cochrane Library. Finally, ten studies with a total of 1736 patients with cancer were included in the present study. Negative/low 5-hmC levels were significantly associated with lymph node metastasis [OR= 2.20, 95% CI= 1.23-3.96, P= 0.008] and advanced TNM stage [OR= 2.89, 95% CI= 1.21-6.92, P= 0.017]. More importantly, negative/low 5-hmC levels were significantly associated with poor prognosis of cancer patients [overall survival: HR= 1.76, 95% CI= 1.41-2.11, P< 0.001; disease free survival: HR= 1.28, 95% CI= 0.60-1.96, P< 0.001]. The results of this meta-analysis indicate that decreased 5-hmC levels are an indicator of poor survival of cancer patients. Given variability related to ethnicity, cancer types and detection methods, additional well-designed studies with larger sample sizes are required to further confirm our findings.
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