Silence of HIN-1 expression through methylation of its gene promoter in gastric cancer

MGMT gene promoter methylation in humoral tissue as biomarker for lung cancer diagnosis: An update meta-analysis

Objective

To investigate O‐6‐methylguanine‐DNA methyltransferase (MGMT) gene promoter methylation in humoral tissue as biomarker for lung cancer diagnosis by pooling relevant open published data.

Methods

Clinical studies relevant to MGMT gene promoter methylation and lung cancer were systematic electronic searched in the databases of Medline, EMBASE, Ovid, Web of Science, and CNKI. Data of true positive (tp), false positive (fp), false negative (fn), and true negative (tn) were extracted from the included studies and made combination. The diagnostic sensitivity, specificity, diagnostic odds ratio (DOR) and summary receiver operating characteristic (SROC) of MGMT gene methylation for lung cancer diagnosis were pooled.

Results

Twelve studies were included in the meta‐analysis. The diagnostic sensitivity, specificity, DOR were 0.39 (95% CI = 0.31–0.49) 0.92 (95% CI = 0.77–0.97), and 4.20 (95% CI = 2.09–8.44), respectively under random effect model. The SROC of MGMT gene methylation for lung cancer diagnosis was 0.58 (95% CI = 0.53–0.62).

Conclusion

MGMT methylation rate was higher in plasma and bronchoalveolar lavage fluid (BLAF) of lung cancer cases compared to controls. High diagnostic specificity indicated that MGMT methylation in plasma and BLAF can be applied as lung cancer confirmation test.

Aberrant promoter methylation of HIN-1 gene may contribute to the pathogenesis of breast cancer: a meta-analysis

We conducted the present meta-analysis of relevant cohort studies to evaluate whether promoter methylation of the high in normal-1 (HIN-1) gene contributes to breast cancer. The MEDLINE (1966 ~ 2013), Cochrane Library (Issue 12, 2013), EMBASE (1980 ~ 2013), CINAHL (1982 ~ 2013), Web of Science (1945 ~ 2013), and Chinese Biomedical (CBM) (1982 ~ 2013) databases were searched without any language restrictions. Meta-analyses were conducted using Stata software (version 12.0; Stata Corporation, College Station, TX, USA). Crude odds ratios (ORs) with their 95 % confidence interval (CI) were calculated. Nine clinical cohort studies that enrolled a total of 693 breast cancer patients were included in the meta-analysis. The results of our meta-analysis demonstrated that HIN-1 methylation frequency in cancer tissue was significantly higher than that of normal and benign tissues (cancer tissue vs. normal tissue: OR = 52.60, 95 % CI = 33.77 ~ 81.92, P < 0.001; cancer tissue vs. benign tissue: OR = 2.38, 95 % CI = 1.53 ~ 3.70, P < 0.001; respectively). Ethnicity-stratified analysis indicated that HIN-1 promoter methylation was correlated with the pathogenesis of breast cancer among both Asians and Caucasians (all P < 0.05). Our findings provide empirical evidence that aberrant HIN-1 promoter methylation may contribute to the pathogenesis of breast cancer. Thus, aberrant HIN-1 promoter methylation could be an independent and important biomarker used in predicting the prognosis and progression of breast cancer.

Lentivirus-mediated siRNA targeting VEGF inhibits gastric cancer growth in vivo

Vascular endothelial growth factor (VEGF), a crucial promoter of blood vessel growth, not only stimulates endothelial cell proliferation, migration and survival, but also increases vascular permeability. The promotion of angiogenesis is a well-known prerequisite for tumor growth, invasion and metastasis. Evidence has shown that VEGF is overexpressed in many types of tumor tissues. Small interfering RNA (siRNA) targeting VEGF may effectively suppress cell proliferation and induce apoptosis in tumor cells. In this study, we aimed to evaluate whether lentivirus-mediated siRNA targeting VEGF inhibits gastric cancer growth in vivo. The transfection of VEGF siRNA into SGC7901 human gastric cancer cells downregulated the expression of VEGF and Bcl-2, but upregulated the expression of p21. In a nude mouse model of subcutaneous xenografts, 24 days after VEGF siRNA treatment, the tumor volume and weight were significantly smaller in the VEGF siRNA group compared to the control scrambled siRNA group. Furthermore, the expression of VEGF, sirtuin 1 (SIRT1), survivin and Bcl-2 was downregulated, whereas the expression of p53 and p21 was upregulated in the tumor cells, indicating that VEGF siRNA induced apoptosis in gastric cancer cells by inhibiting SIRT1 expression, leading to p53 transcriptional upregulation and the activation of downstream p21, while suppressing Bcl-2 and survivin expression. Our results demonstrate that lentivirus-mediated siRNA targeting VEGF offers a potential strategy to prevent the growth of gastric cancer.