Increased risk of breast cancer in individuals carrying the TNRC9 rs3803662 C>T polymorphism: a meta-analysis of case-control studies.

Currently, the relationship between the trinucleotide repeat containing 9 (TNRC9) rs3803662 C>T polymorphism and risk of breast cancer (BC) is uncertain. Here, we attempted to obtain a more accurate assessment of this association by conducting a meta-analysis of all eligible case-control investigations, comprising 44,820 cases and 58,316 controls. A comprehensive search was performed to identify all suitable studies involving the TNRC9 rs3803662 polymorphism and BC risk. Pooled odds ratios (ORs) and 95% confidence intervals (95%CIs) were estimated using fixed- or random-effect models. Heterogeneity, publication bias, and sensitivity analyses were also carried out. We found that the variant T allele of rs3803662 C>T greatly increases BC risk (CT vs CC: OR = 1.14, 95%CI = 1.07-1.22, P < 0.001; TT vs CC: OR = 1.38, 95%CI = 1.25-1.53, P < 0.001; CT/TT vs CC: OR = 1.19, 95%CI = 1.11-1.28, P < 0.001; TT vs CT/CC: OR = 1.28, 95%CI = 1.19-1.38, P < 0.001). Stratified analysis based on ethnicity also revealed a markedly increased risk in Asian and Caucasian populations. Moreover, studies with hospital-based control groups showed elevated risk under the four genetic models employed, as did those using population-based controls, except under heterozygote comparison. The TNRC9 rs3803662 C>T polymorphism is greatly related to increased risk of BC, in both Asian and Caucasian populations.

Glutathione S-transferase P1 rs1695 A>G polymorphism and breast cancer risk: evidence from a meta-analysis.

Breast cancer (BC) is the most widespread cause of cancer-related deaths in women. Many published studies have assessed the association between the glutathione S-transferase P1 (GSTP1) rs1695 polymorphism and BC risk. However, the effect of the GSTP1 rs1695 polymorphism on BC risk has remained controversial. Therefore, this meta-analysis was conducted to obtain a comprehensive estimation of this association. A total of 20,615 cases and 20,481 controls from thirty-six case-control trials were extracted from an online literature survey. The meta-analysis indicated that the GSTP1 rs1695 A>G polymorphism did not contribute to the susceptibility of BC when the overall population was considered. However, intriguingly, this polymorphism was significantly associated with increased risk of BC in Asian women [GG vs AA: odds ratio (OR) = 1.4, 95% confidence interval (CI): 1.06-1.88, P = 0.02; AG vs AA: OR = 1.08, 95%CI = 1.00-1.16, P = 0.05; GG/AG vs AA: OR = 1.11, 95%CI = 1.04-1.19, P = 0.00]. Moreover, a subgroup analysis based on the source of control groups showed a marked increase in BC susceptibility in hospital-based control subjects (GG vs AA: OR = 1.28, 95%CI = 1.10-1.48, P= 0.00; GG vs AG/AA: OR = 1.22, 95%CI = 1.06-1.41, P = 0.00; GG/AG vs AA: OR = 1.10, 95%CI = 1.02-1.18, P = 0.00). In conclusion, our study indicated that the GSTP1 rs1695 A>G polymorphism was correlated with elevated BC risk in Asian women. Our results must be validated with further research.

Implicating the H63D polymorphism in the HFE gene in increased incidence of solid cancers: a meta-analysis.

A number of previous studies have demonstrated that the HFE H63D polymorphism is associated with increased risk of incidence multiple types of cancer, including colorectal cancer, breast cancer, liver cancer, pancreatic cancer, and gynecological malignant tumors. However, the clinical outcomes were inconsistent. Therefore, this meta-analysis was conducted to summarize the effect of the H63D variant on the incidence of solid tumor. PubMed and EMBASE databases were searched for articles associating the HFE H63D polymorphism with cancer risk. The relationships were evaluated by calculating the pooled odds ratios (ORs) with 95% confidence intervals (CIs). A total of 28 studies, including 7728 cancer cases and 11,895 controls, were identified. Statistically significant associations were identified between the HFE H63D polymorphism and solid cancer risk (CG vs CC, OR = 1.14, 95%CI = 1.07-1.23, P < 0.001; GG vs CC, OR = 1.28, 95%CI = 1.06-1.55, P = 0.010; CG/GG vs CC, OR = 1.16, 95%CI = 1.08-1.24, P < 0.001; GG vs CC/CG, OR = 1.24, 95%CI = 1.02-1.49, P = 0.027). In the subgroup analysis, we illustrated the effect of the H63D polymorphism on hepatocellular carcinoma and pancreatic cancer risk, particularly in the Asian and African subgroups; however, this was not observed in gynecological malignant tumors. In summary, this analysis provided strong evidence that the HFE H63D polymorphism may play a critical role in the increased aggressiveness of hepatocellular carcinoma and pancreatic cancer.

Clinical significance of SHMT1 rs1979277 polymorphism in Asian solid tumors: evidence from a meta-analysis.

Published data regarding the association between the cytosolic serine hydroxymethyltransferase (SHMT1) C1420T (Leu474Phe) polymorphism and solid tumor risk have shown inconclusive results. To derive a more precise estimation of the relationship, we performed a meta-analysis of 23 published studies that included 14,409 cancer cases and 16,996 controls. A comprehensive search was conducted to identify all eligible studies of the SHMT1 rs1979277 polymorphism and solid tumor risk. The pooled odds ratios (ORs) and the 95% confidence intervals (95%CIs) were calculated using a fixed- or random-effects model. Heterogeneity was represented by PH; publication bias and sensitivity analysis were also explored. Overall, no significant associations were found for any genetic models tested. However, upon stratification by cancer type, a significant decreased risk of breast cancer risk was identified in the homozygote comparison (OR = 0.79, 95%CI = 0.65-0.97 for TT versus CC). An analysis stratified by ethnicity and source of controls revealed an obvious decrease in risk among Asian groups in all genetic models, and among population-based controls only in the homozygote comparison and recessive model. Therefore, our meta-analysis suggested that the SHMT1 C1420T polymorphism was associated with decreased risk of breast cancer. Significant protective effects were found among Asian populations, but not in Caucasian groups. Due to some minor limitations, our findings should be confirmed by further studies.

Expression analysis of differentially expressed miRNAs in male and female chicken embryos.

MicroRNAs (miRNAs) are small non-coding RNA molecules that play key roles in the regulation of development processes of many tissues and organs at the post-transcriptional level. However, little is known about how they affect chicken gonadal development. We examined the expression of four miRNAs (miR-218, -200b, -196, and -206) in chicken embryonic gonads at embryonic days 3.5-6.5. Their target genes were predicted by miRDB, TargetScan and PicTar algorithms. The expression levels of these four miRNAs differed with sex to varying degrees; miR-200b was expressed at a significantly higher level in female gonads during the entire interval. The whole mount in situ hybridization result showed considerably higher expression of miR-200b in females than in males in E5.5 embryos. The miRNA target scanning results indicated several genes with functions in gonad development and gonad function. We conclude that miR-200b is involved in the regulation of gonad development and sexual differentiation of chicken embryos.

Decreased risk of developing lung cancer in subjects carrying the CLPTM1L rs401681 (G>A) polymorphism: evidence from a meta-analysis.

A genome-wide association study revealed that a single nucleotide polymorphism, CLPTM1L - rs401681 (G>A), located at the 5p15.33 locus was significantly associated with increased risk of various cancers; however, its association with lung cancer is currently inconclusive. In order to explore the relationship between this polymorphism and lung cancer risk more precisely, we performed a meta-analysis of eight eligible studies involving 9935 cases and 11,261 controls. The pooled odds ratio (OR) and the 95% confidence interval (CI) were calculated using a fixed- or random-effect models. Results indicated that this polymorphism was significantly associated with lung cancer risk in all genetic models (GA vs GG: OR = 0.88, 95%CI = 0.83-0.94; AA vs GG: OR = 0.81, 95%CI = 0.70-0.93; AA/GA vs GG: OR = 0.86, 95%CI = 0.81-0.91; AA vs GA/GG: OR = 0.86, 95%CI = 0.76-0.99). An analysis stratified by ethnicity and source of controls revealed a significantly decreased risk among European groups and population-based studies in all genetic models, and among Asian populations only in the dominant model comparison. Additionally, in a subgroup analysis by histology type, the CLPTM1L rs401681 polymorphism was found to significantly decrease the risks of both adenocarcinoma and squamous cell carcinoma of the lung in all genetic models. In conclusion, our study indicated that the CLPTM1L - rs401681 (G>A) polymorphism was significantly associated with decreased lung cancer risk, especially among European populations. Due to some minor limitations, our findings should be confirmed in further studies.