Recent years have witnessed the discovery of similar gene variations between breast cancer and ovarian cancer, inherited breast and ovarian cancer in particular. A large number of case-control studies have been conducted to explore the association of Methylenetetrahydrofolate Reductase (MTHFR) A1298C polymorphism with breast cancer and/or ovarian cancer risk. However, the results are still inconsistent and inconclusive. Consequently, we performed a meta-analysis to evaluate the association between MTHFR A1298C polymorphism and breast, ovarian cancer risk.

Precision cancer medicine depends on defining distinct tumour subgroups using biomarkers that may occur at very modest frequencies. One such subgroup comprises patients with exceptionally mutated (ultramutated) cancers caused by mutations that impair DNA polymerase epsilon (POLE) proofreading.

It has been suggested that long non-coding RNA (lncRNA) gene polymorphisms are associated with cancer risk. In this article, we conducted a systematic review related to studies on the association between lncRNA single-nucleotide polymorphisms (SNPs) and the overall risk of cancer. A total 17 SNPs in four common lncRNA genes were included in the meta-analysis. In the lncRNA H19, the rs2735971 A/G, rs2839698C/T, and rs3024270 G/C polymorphisms, but not rs217727C/T, were correlated with overall cancer risk. The results also suggested that other SNPs were correlated with overall cancer risk, namely, two in HOTAIR (HOX transcript antisense RNA: rs920778C/T and rs7958904 G/C) and two in PRNCR1 (rs1016343C/T and rs16901946 A/G). No association was found between the three ZNRD1-AS1 (ZNRD1 antisense RNA 1) SNPs and the risk of cancer. In summary, our findings suggest that quite a few studied lncRNA SNPs are associated with overall cancer risk; therefore, they are potential predictive biomarkers for the risk of cancer. Moreover, other lncRNA SNPs investigated were also relevant to cancer but studies on them are limited, and they were also briefly reviewed as candidate cancer markers.

The association between the polymorphic GGN repeat in androgen receptor gene and prostate cancer susceptibility has been studied extensively. But the results of these polymorphisms with prostate cancer risk remain inconclusive. Previous meta-analysis showed short GGN repeats (≤16 repeats) had high risks for prostate cancer compared with longer GGN repeats (>16 repeats). Many studies have been published since the release of the previous meta-analysis. Here, we conducted an updated meta-analysis to demonstrate whether short repeats have higher risks for prostate cancer compared to long repeats. Five databases (PubMed, EMBASE, Cochrane Library, The China National Knowledge Infrastructure, and Web of Science) were last searched until January 1, 2016. Random- or fixed-effects model was performed based on the heterogeneity among studies. The potential publication bias was assessed via Begg funnel plot and Egger regression test. Twelve out of 157 studies were extracted. The result indicated that there was no significant difference between short repeat group and long repeat group in the overall analysis ( I2 = 80.6%, P = .000, odds ratio = 1.31, 95% confidence interval: 0.93-1.83). There was no association between the length of GGN repeats and the occurrence of prostate cancer in both Caucasian and African American ( I2 = 6.7%, P = .359, odds ratio = 1.11, 95% confidence interval: 0.94-1.32; and I2 = 74.1%, P = .050, odds ratio = 0.963, 95% confidence interval: 0.36-2.58). Our result demonstrated that a shorter GGN repeat polymorphism cannot increase the risk of prostate cancer compared to the longer GGN repeats. That's different with previous meta-analysis.

The purpose of this meta-analysis was to evaluate the association between cyclooxygenase-2 (Cox-2) expression and skin cancer.

X-ray cross-complementing groups 1 (XRCC1) rs1799782 C>T polymorphisms and colorectal cancer susceptibility were not clear. The purpose of this study was to evaluate the association between XRCC1 rs1799782 C>T polymorphisms and colorectal cancer susceptibility by meta-analysis.

To evaluate O-6-methylguanine-DNA methyltransferase (MGMT) gene promoter methylation pattern in tumor tissue and autologous controls (plasma, normal lung tissue, and bronchial lavage fluid [BLF]) in patients with nonsmall cell lung cancer (NSCLC).

The aim of this meta-analysis is to evaluate the distribution pattern of KRAS and BRAF mutations in colorectal cancer.

Multiple breast cancer loci have been identified in previous genome-wide association studies, but they were mainly conducted in populations of European ancestry. Women of African ancestry are more likely to have young-onset and oestrogen receptor (ER) negative breast cancer for reasons that are unknown and understudied. To identify genetic risk factors for breast cancer in women of African descent, we conducted a meta-analysis of two genome-wide association studies of breast cancer; one study consists of 1,657 cases and 2,029 controls genotyped with Illumina’s HumanOmni2.5 BeadChip and the other study included 3,016 cases and 2,745 controls genotyped using Illumina Human1M-Duo BeadChip. The top 18,376 single nucleotide polymorphisms (SNP) from the meta-analysis were replicated in the third study that consists of 1,984 African Americans cases and 2,939 controls. We found that SNP rs13074711, 26.5 Kb upstream of TNFSF10 at 3q26.21, was significantly associated with risk of oestrogen receptor (ER)-negative breast cancer (odds ratio [OR]=1.29, 95% CI: 1.18-1.40; P = 1.8 × 10 − 8). Functional annotations suggest that the TNFSF10 gene may be involved in breast cancer aetiology, but further functional experiments are needed. In addition, we confirmed SNP rs10069690 was the best indicator for ER-negative breast cancer at 5p15.33 (OR = 1.30; P = 2.4 × 10 − 10) and identified rs12998806 as the best indicator for ER-positive breast cancer at 2q35 (OR = 1.34; P = 2.2 × 10 − 8) for women of African ancestry. These findings demonstrated additional susceptibility alleles for breast cancer can be revealed in diverse populations and have important public health implications in building race/ethnicity-specific risk prediction model for breast cancer.

Growing evidence from studies has shown that microRNA-196a (miR-196a) is correlated with treatment response and prognosis in Asian cancer patients. However, the studies reveal that the role of miR-196a is not totally consistent, making it rational to perform a meta-analysis to assess the prognostic value of miR-196a in cancers.

microRNAs are widely involved in a variety of life processes and considered as potential biomarkers of tumor prognosis. A growing number of studies have documented that miRNAs were associated with outcome in NSCLC patients and can act as a prognostic marker. However, existing studies concerning the relationship between miRNAs and outcome in NSCLC patients were contentious and dispersive. Therefore, a systematic metaanalysis to explore the prognostic value of miRNAs on NSCLC patients is urgently needed.

Many studies demonstrated that the expression level of HOTTIP in cancerous tissues was significantly higher than that in adjacent normal tissues. Increased expression of HOTTIP was associated with metastasis and a poor prognosis.

Published data on the association between present/null polymorphism of glutathione S-transferase M1 (GSTM1) and breast cancer risk are inconclusive. To derive a more precise estimation of the relationship, a meta-analysis in the Chinese population was performed.

MicroRNAs (miRNAs) play important roles in cancer development. MiR-222, which is deregulated in multiple types of cancers, shows potential as a prognostic biomarker; however, the association between miR222 expression and cancer prognosis was controversial in previous studies. Here we analyzed the relationship between miR-222 and the survival of cancer patients.

Although many epidemiological studies have investigated the CYP1A1 exon7 polymorphism and -GSTM1 interaction with esophageal cancer (EC), definite conclusions cannot be drawn. This study was conducted to explore this association in the Chinese population using meta-analysis.

Purpose: Androgen receptor (AR) expression has been observed in about 70% of patients with breast cancer, but its prognostic role remains uncertain.Experimental Design: To assess the prognostic role of AR expression in early-stage breast cancer, we performed a meta-analysis of studies that evaluated the impact of AR at the protein and gene expression level on disease-free survival (DFS) and/or overall survival (OS). Eligible studies were identified by systematic review of electronic databases using the MeSH-terms "breast neoplasm" and "androgen receptor" and were selected after a qualitative assessment based on the REMARK criteria. A pooled gene expression analysis of 35 publicly available microarray data sets was also performed from patients with early-stage breast cancer with available gene expression and clinical outcome data.Results: Twenty-two of 33 eligible studies for the clinical meta-analysis, including 10,004 patients, were considered as evaluable for the current study after the qualitative assessment. AR positivity defined by IHC was associated with improved DFS in all patients with breast cancer [multivariate (M) analysis, HR 0.46; 95% confidence interval (CI) 0.37-0.58, P < 0.001] and better OS [M-HR 0.53; 95% CI, 0.38-0.73, P < 0.001]. Thirty-five datasets including 7,220 patients were eligible for the pooled gene expression analysis. High AR mRNA levels were found to confer positive prognosis overall in terms of DFS (HR 0.82; 95% CI 0.72-0.92;P = 0.0007) and OS (HR 0.84; 95% CI, 0.75-0.94; P = 0.02) only in univariate analysis.Conclusions: Our analysis, conducted among more than 17,000 women with early-stage breast cancer included in clinical and gene expression analysis, demonstrates that AR positivity is associated with favorable clinical outcome. Clin Cancer Res; 23(11); 2702-12. ©2016 AACR.

Some studies investigated the association of paraoxonase 1 (PON1) polymorphisms with polycystic ovarian syndrome (PCOS) risk. However, the result was still inconsistent. The aim of this study was to investigate whether there is an association between the PON1 polymorphisms and PCOS risk. Electronic databases, such as PubMed, EMBASE, and China National Knowledge Infrastructure (CNKI) databases, were searched for identification of the studies. The associations between PON1 polymorphisms and PCOS risk was quantified using ORs with 95% CIs. A total of 8 eligible studies with 2272 cases and 1811 controls were included in this meta-analysis. PON1 Leu55Met polymorphism was associated with a significantly increased risk of PCOS (OR=1.31; 95%CI, 1.10-1.55). However, no association was found in Asians and Caucasians (Table 2). We also found that PON1 Q192R polymorphism was associated with a significantly increased risk of PCOS (OR=1.81; 95%CI, 1.17-2.82). Additionally, this polymorphism increased PCOS risk in Asians (OR=1.26; 95%CI, 1.13-1.41). Furthermore, PON1 C108T polymorphism showed increased PCOS risk (OR=1.46; 95%CI, 1.08-1.97). No association between this polymorphism and PCOS risk was found in Asians and Caucasians. In conclusion, this meta-analysis suggested that PON1 polymorphisms were associated with PCOS risk.

Objectives. To investigate the potential association of tumor necrosis factor-α T-857C polymorphism with susceptibility to the five common malignant tumors. Materials and Methods. A comprehensive search of PubMed/Medline, Embase, and Web of Science databases was performed up to November 2015. Pooled odds ratios (ORs) and 95% confidence intervals (95% CIs) were calculated to assess the strength of the association. Subgroup analysis, heterogeneity analyses, and publication bias were also texted in the meta-analysis. Results. A total of twenty-two publications involving 5215 cases and 6755 controls were recruited. Overall, the meta-analysis revealed an increased risk between the TNF-α T-857C polymorphism and gastric cancer susceptibility in T versus C model, heterozygote genetic model, and dominant genetic model. An increased risk between the TNF-α T-857C polymorphism and hepatocellular cancer susceptibility in homozygote genetic model and recessive genetic model was also found. No significant association was found between the TNF-α T-857C polymorphism and colorectal cancer, cervical cancer, and prostate cancer. Conclusions. Our meta-analyses suggest that TNF-α T-857C polymorphism may be associated with increased risk of gastric cancer and hepatocellular cancer development. Therefore, the TNF-α T-857C polymorphism could be considered as one possible risk factor of gastric cancer and hepatocellular cancer according to our study.

To systematically review the prognostic value regarding the expression of long non-coding RNA (lncRNA) Hox transcript antisense intergenic RNA (HOTAIR) in patients with cancer. 
 Methods: Databases including The Cochrane Library, EMBASE, MEDLINE, and PubMed were searched to collect English literature on the correlation between lncRNA HOTAIR expression and overall survival in tumors. The retrieval time was from inception to September 2015. After data were extracted, a Meta-analysis was performed using RevMan 5.3 software.
 Results: A total of 17 studies were included, which was involved in 1 639 patients. The Meta-analysis showed that high expression of HOTAIR could predict poor overall survival in cancer (HR: 2.39, 95% CI 2.01-2.86, P<0.001). High expression of HOTAIR could also predict poor overall survival both in digestive tumor (HR: 2.51, 95% CI 2.02-3.11, P<0.001) and non-digestive tumor (HR: 2.17, 95% CI 1.59-2.98, P<0.001). Moreover, overexpression of HOTAIR was found to be significantly associated with recurrence-free survival.
 Conclusion: The overexpression of lncRNA HOTAIR might be associated with poor prognosis in patients with cancer.

Mothers against decapentaplegic homolog 7 (SMAD7) inhibits the transforming growth factor-β (TGF-β) signaling pathway, which regulates carcinogenesis and cancer progression. A number of studies have reported that SMAD7 polymorphisms (rs4464148, rs4939827, and rs12953717) are associated with colorectal cancer (CRC) risk, but the results from these studies remain conflicting. To determine a more precise estimation of the relationship between SMAD7 and CRC, we undertook a large-scale meta-analysis of 63 studies, which included a total of 187,181 subjects (86,585 cases and 100,596 controls). The results of our meta-analysis revealed that the C allele of rs4464148 [CC vs. TT+TC, odds ratio (OR) =1.23, 95% confidence interval (CI): 1.14-1.33, P < 0.01], the T allele of rs4939827 [TT vs. CC+TC, odds ratio OR=1.15, 95%CI:1.07-1.22, P < 0.01] and the T allele of rs12953717 [TT vs. CC+TC, OR =1.22, 95%CI:1.16-1.29, P < 0.01] were all associated with the increased CRC risk. Subgroup analysis according to ethnicity showed rs4464148 and rs12953717 were associated with the risk of CRC in both Caucasians and Asians, whereas rs4939827 was a risk polymorphism for CRC specifically in Caucasians. In summary, this large-scale meta-analysis indicated that SMAD7 polymorphisms (rs4464148, rs4939827, and rs12953717) correlate with CRC.