ALDH5A1 acts as a tumour promoter and has a prognostic impact in papillary thyroid carcinoma.

Thyroid cancer is the most common endocrine carcinoma, with papillary thyroid carcinoma (PTC) accounting for 80%-90% of thyroid cancers. Accumulating studies reported that mitochondria plays an important role in the regulation of cell proliferation. ALDH5A1, may function as an oncogene or tumour suppressor in various human cancers, and the role of ALDH5A1 in PTC is still unclear. The aim of this study was to investigate the clinical significance of ALDH5A1 expression and its functions in PTC. In this present study, we studied ALDH5A1 expression on primary papillary thyroid carcinoma (PTC) in The Cancer Genome Atlas (TCGA) database. Results showed that the levels of ALDH5A1 were found positively correlated with tumour stage, metastasis, lymph node stage, and higher levels of ALDH5A1 demonstrated poor disease-free survival (DFS). Immunohistochemistry (IHC) revealed that significantly higher expression of ALDH5A1 was found in PTC tissues. On the other hand, knockdown of ALDH5A1 significantly inhibited PTC cell proliferation, migration and invasion detection found the migration and invasion of cells also were hindered when ALDH5A1 level was reduced. The knockdown of ALDH5A1 inhibited the expression of Vimentin and promoted the expression of E-cadherin. In brief, knockdown of ALDH5A1may act as a novel molecular target for the prevention and treatment of PTC. SIGNIFICANCE OF THE STUDY: The present study focused on the role and the potential mechanism of ALDH5A1 in papillary thyroid carcinoma. We demonstrated that reduced expression of ALDH5A1 might inhibit the progression of TC by inhibiting cell proliferation, migration and invasion and reversing epithelial-mesenchymal transition (EMT). The findings ensured the interaction relation between ALDH5A1 and EMT in PTC, providing a novel biological marker for PTC and enriching the potential strategies for TC treatment.

MiR-384 regulated IRS1 expression and suppressed cell proliferation of human hepatocellular carcinoma.

Acquired evidence indicated that microRNAs (miRNAs) played essential roles in cancer development, including hepatocellular carcinoma (HCC). Functions and mechanisms of miRNAs involved in HCC remain largely unknown. Here, we found that miR-384 was significantly downregulated in HCC cells and tissues by RT-PCR. Gain and loss of function studies revealed that miR-384 significantly suppressed HCC cell proliferation. Insulin receptor substrate 1(IRS1) was identified as a direct and functional target of miR-384. Moreover, miR-384 decreased IRS1 expression, subsequently downregulating cyclin D1 and upregulating p21 and p-Rb expression. In addition, promotion of cell proliferation caused by miR-384-in was counteracted by silencing IRS1 expression with siRNAs. Taken together, our data provided convincing evidence that miR-384 exerted suppressive effect on HCC cell proliferation through the direct inhibition of IRS1 expression, suggesting miR-384 may serve as a potential therapeutic target for HCC.

MiR-492 contributes to cell proliferation and cell cycle of human breast cancer cells by suppressing SOX7 expression.

MicroRNAs (miRNAs) have emerged as important regulators that potentially play critical roles in cancer cell biological processes. Previous studies have shown that miR-492 plays an important role in cell tumorigenesis in multiple kinds of human cancer cells. However, the underlying mechanisms of this microRNA in breast cancer remain largely unknown. In the present study, we investigated miR-492's role in cell proliferation of breast cancer. MiR-492 expression was markedly upregulated in breast cancer tissues and breast cancer cells. Overexpression of miR-492 promoted the proliferation and anchorage-independent growth of breast cancer cells. Bioinformatics analysis further revealed sex-determining region Y-box 7 (SOX7), a putative tumor suppressor, as a potential target of miR-492. Data from luciferase reporter assays showed that miR-492 directly binds to the 3'-untranslated region (3'-UTR) of SOX7 messenger RNA (mRNA) and repressed expression at both transcriptional and translational levels. Ectopic expression of miR-492 led to downregulation of SOX7 protein, which resulted in the upregulation of cyclin D1 and c-Myc. In functional assays, SOX7 silenced in miR-492-in-transfected ZR-75-30 cells has positive effect to promote cell proliferation, suggesting that direct SOX7 downregulation is required for miR-492-induced cell proliferation and cell cycle of breast cancer. In sum, these results suggest that miR-492 represents a potential onco-miR and participates in breast cancer carcinogenesis by suppressing SOX7 expression.

Protease-activated receptor-2 modulates hepatic stellate cell collagen release and apoptotic status.

The pathogenesis of hepatic fibrosis is to be further investigated. Protease-activated receptor-2 (PAR2) plays a role in hepatic fibrosis. This study aims to elucidate the role of activation of PAR2 in the regulation of hepatic stellate cell activities. In this study, the expression of PAR2, Fas and caveolin-1 in human hepatic stellate cell line, HHStec cell (HHStecs) was assessed by real time RT-PCR and Western blot. The levels of collagen were determined by enzyme-linked immunosorbent assay. The PAR2 gene was silenced in HHStecs using RNA interference. Apoptosis of HHStecs was assessed by flow cytometry. The results showed that HHStecs expressed PAR2, which was up regulated by activation with phorbol myristate acetate (PMA). Activation of PAR2 increased the release of collagen from HHStecs. Exposure to PMA induced HHStec apoptosis, which was significantly inhibited by activation of PAR2. The PAR2 activation also suppressed the expression of caveolin-1 and Fas in HHStecs. Over expression of caveolin-1 in HHStecs blocked PAR2-reduced apoptosis. We conclude that HHStecs express PAR2. Activation of PAR2 increases HHStecs to release collagen and reduces the activation-induced HHStec apoptosis, which can be inhibited by the over expression of caveolin-1.

Activated protease receptor-2 induces GATA6 expression to promote survival in irradiated colon cancer cells.

BACKGROUND AND AIMS: The resistance to irradiation is common and a great drawback in the treatment of cancer with radiotherapy; the underlying mechanism is unclear. GATA binding protein 6 (GATA6) is associated with the pathogenesis of cancer. This study aims to investigate the role of GATA6 on compromising irradiation effect on HT55 and HT29 cells, 2 colorectal cancer cell lines. METHODS: Human colon cancer cell lines, HT55 and HT29 cells, were treated with irradiation in the culture. Apoptosis of HT55 and HT29 cells was determined by flow cytometry. The expression of PAR2 and GATA6 in HT55 and HT29 cells was analyzed by real time RT-PCR and Western blotting. The gene silence and gene over expression were employed to observe the effect of GATA6 on p53 expression in HT55 and HT29 cells. RESULTS: The results showed that HT55 and HT29 cells expressed protease-activated receptor-2 (PAR2). Irradiation induced 38.6% HT55 cell and 33.8% HT29 cell apoptosis, which reduced to 4.2% and 5.6%, respectively after activation of PAR2. Exposure to irradiation increased the expression of GATA6; the latter played a critical role in suppression of p53 expression in HT55 and HT29 cells. Inhibition of GATA6 significantly increased the effect of irradiation on HT55 and HT29 cells. CONCLUSIONS: Activation of PAR2 compromises the effect of irradiation on inducing colorectal cancer cell apoptosis, which can be prevented by inhibition of GATA6 expression.

Identification of a 3-Gene Prognostic Index for Papillary Thyroid Carcinoma.

The accurate determination of the risk of cancer recurrence is a critical unmet need in managing thyroid cancer (TC). Although numerous studies have successfully demonstrated the use of high throughput molecular diagnostics in TC prediction, it has not been successfully applied in routine clinical use, particularly in Chinese patients. In our study, we objective to screen for characteristic genes specific to PTC and establish an accurate model for diagnosis and prognostic evaluation of PTC. We screen the differentially expressed genes by Python 3.6 in The Cancer Genome Atlas (TCGA) database. We discovered a three-gene signature Gap junction protein beta 4 (GJB4), Ripply transcriptional repressor 3 (RIPPLY3), and Adrenoceptor alpha 1B (ADRA1B) that had a statistically significant difference. Then we used Gene Expression Omnibus (GEO) database to establish a diagnostic and prognostic model to verify the three-gene signature. For experimental validation, immunohistochemistry in tissue microarrays showed that thyroid samples' proteins expressed by this three-gene are differentially expressed. Our protocol discovered a robust three-gene signature that can distinguish prognosis, which will have daily clinical application.

Network Pharmacology to Explore the Molecular Mechanisms of Prunella vulgaris for Treating Hashimoto's Thyroiditis.

Purpose: Prunella vulgaris (PV), a traditional Chinese medicine, has been used to treat patients with thyroid disease for centuries in China. The purpose of the present study was to investigate its bioactive ingredients and mechanisms against Hashimoto's thyroiditis (HT) using network pharmacology and molecular docking technology to provide some basis for experimental research. Methods: Ingredients of the PV formula were retrieved from the Traditional Chinese Medicine Systems Pharmacology (TCMSP) database. Additionally, HT-related genes were retrieved from the UniProt and GeneCards databases. Cytoscape constructed networks for visualization. A protein-protein interaction (PPI) network analysis was constructed, and a PPI network was built using the Search Tool for the Retrieval of Interacting Genes (STRING) database. These key targets of PV were enriched and analyzed by molecular docking verification, Gene Ontology (GO), and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment. Results: The compound-target network included 11 compounds and 66 target genes. Key targets contained Jun proto-oncogene (JUN), hsp90aa1.1 (AKI), mitogen-activated protein kinase 1 (MAPK1), and tumor protein p53 (TP53). The main pathways included the AGE-RAGE signaling pathway, the TNF signaling pathway, the PI3K-Akt signaling pathway, and the mitogen-activated protein kinase signaling pathway. The molecular docking results revealed that the main compound identified in the Prunella vulgaris was luteolin, followed by kaempferol, which had a strong affinity for HT. Conclusion: Molecular docking studies indicated that luteolin and kaempferol were bioactive compounds of PV and might play an essential role in treating HT by regulating multiple signaling pathways.

Significance of DMBT1 in Papillary Thyroid Carcinoma Concurrent With Hashimoto's Thyroiditis.

BACKGROUND: Papillary thyroid carcinoma (PTC) concurrent with Hashimoto's thyroiditis (HT) was associated with a better clinical prognosis. This study aimed to investigate a potential mRNA gene that affects the development of PTC, which helps PTC concurrent with HT patients have a better prognosis. MATERIAL/METHODS: PTC data were obtained from The Cancer Genome Atlas (TCGA) database. And the validation data of tissue specimens were collected from Guangzhou First People's Hospital. The thyroid tissue sections were hybridized with deleted in malignant brain tumor 1 (DMBT1) probes by situ hybridization. Survival rates were analyzed using Kaplan-Meier curves, and the log-rank test was used to compare group survival rates. Prognosis clinicopathological factors were analyzed by Cox regression. Gene Ontology (GO) and Kyoto Gene and Genomic Encyclopedia (KEGG) pathway enrichment analyses were performed using single-sample gene set enrichment analysis (ssGSEA). Finally, the correlation of deletion in DMBT1 expression with overall immune status, tumor purity, and human leukocyte antigen (HLA) gene expression profile was analyzed. RESULTS: HT was significantly associated with sex, tumor foci, extrathyroidal extension (ETE), residual tumor, and tumor stage (T stage). Moreover, PTC concurrent with HT had a lower risk of recurrence versus non-HT groups. A total of 136 differentially expressed mRNAs (DEMs) were identified between HT and non-HT groups. Among them, the expression level of DMBT1 in HT groups was statistically higher than that in non-HT groups. A significant association with ETE and recurrence was revealed in the high expression and the low expression of DMBT1. Furthermore, DMBT1 was an independent predictor of survival. The overall immune activity of high expression of DMBT1 was higher than that of the low-expression group. CONCLUSIONS: The PTC patients with HT had better behavior features and prognosis than those with simple PTC. DMBT1 in PTC-HT patients was a potential possible factor that inhibits tumors. High expression of DMBT1 may improve PTC prognosis by immune-related pathways.

Prioritizing Susceptible Genes for Thyroid Cancer Based on Gene Interaction Network.

Thyroid cancer ranks second in the incidence rate of endocrine malignant cancer. Thyroid cancer is usually asymptomatic at the initial stage, which makes patients easily miss the early treatment time. Combining genetic testing with imaging can greatly improve the diagnostic efficiency of thyroid cancer. Researchers have discovered many genes related to thyroid cancer. However, the effects of these genes on thyroid cancer are different. We hypothesize that there is a stronger interaction between the core genes that cause thyroid cancer. Based on this hypothesis, we constructed an interaction network of thyroid cancer-related genes. We traversed the network through random walks, and sorted thyroid cancer-related genes through ADNN which is fusion of Adaboost and deep neural network (DNN). In addition, we discovered more thyroid cancer-related genes by ADNN. In order to verify the accuracy of ADNN, we conducted a fivefold cross-validation. ADNN achieved AUC of 0.85 and AUPR of 0.81, which are more accurate than other methods.

MicroRNA-3690 promotes cell proliferation and cell cycle progression by altering DKK3 expression in human thyroid cancer.

An increasing amount of evidence has demonstrated the importance of microRNAs (miRNAs/miRs) in the tumorigenesis of malignant types of cancer, and data retrieved from The Cancer Genome Atlas database revealed that miR-3690 was upregulated in thyroid cancer (TC). The present study focused on the biological function and mechanism of miR-3690 in TC, demonstrating that miR-3690 expression was significantly elevated in TC cells and clinical tissues. Functional studies indicated that miR-3690 acted as an oncogene in TC by promoting cell proliferation, colony formation and cell cycle progression in association with the increased expression of cyclin E and c-myc. Mechanistically, prediction software indicated that Dickkopf-related protein 3 (DKK3) was a target of miR-3690, which was confirmed by the results of luciferase reporter assays and western blotting. DKK3 silencing abrogated the functions of miR-3690-in on TC cell proliferation. Collectively, the findings of the present study demonstrated that miR-3690 promoted TC cell proliferation and indicated miR-3690 as a potential biomarker and therapeutic target for TC.

Potential five-mRNA signature model for the prediction of prognosis in patients with papillary thyroid carcinoma.

Although the mortality rate of papillary thyroid carcinoma (PTC) is relatively low, the recurrence rates of PTC remain high. The high recurrence rates are related to the difficulties in treatment. Gene expression profiles has provided novel insights into potential therapeutic targets and molecular biomarkers of PTC. The aim of the present study was to identify mRNA signatures which may categorize PTCs into high-and low-risk subgroups and aid with the predictions for prognoses. The mRNA expression profiles of PTC and normal thyroid tissue samples were obtained from The Cancer Genome Atlas (TCGA) database. Differentially expressed mRNAs were identified using the 'EdgeR' software package. Gene signatures associated with the overall survival of PTC were selected, and enrichment analysis was performed to explore the biological pathways and functions of the prognostic mRNAs using the Database for Visualization, Annotation and Integration Discovery. A signature model was established to investigate a specific and robust risk stratification for PTC. A total of 1,085 differentially expressed mRNAs were identified between the PTC and normal thyroid tissue samples. Among them, 361 mRNAs were associated with overall survival (P<0.05). A 5-mRNA prognostic signature for PTC (ADRA1B, RIPPLY3, PCOLCE, TEKT1 and SALL3) was identified to classify the patients into high-and low-risk subgroups. These prognostic mRNAs were enriched in Gene Ontology terms such as 'calcium ion binding', 'enzyme inhibitor activity', 'carbohydrate binding', 'transcriptional activator activity', 'RNA polymerase II core promoter proximal region sequence-specific binding' and 'glutathione transferase activity', and Kyoto Encyclopedia of Genes and Genomes signaling pathways such as 'pertussis', 'ascorbate and aldarate metabolism', 'systemic lupus erythematosus', 'drug metabolism-cytochrome P450 and 'complement and coagulation cascades'. The 5-mRNA signature model may be useful during consultations with patients with PTC to improve the prediction of their prognosis. In addition, the prognostic signature identified in the present study may reveal novel therapeutic targets for patients with PTC.

Targeting of TLE3 by miR-3677 in human breast cancer promotes cell proliferation, migration and invasion.

Numerous studies have indicated an important function of microRNAs (miRs) in breast cancer (BC) progression, oncogenesis and metastasis. However, the function of miR-3677, which has been revealed to be upregulated in BC [The Cancer Genome Atlas (TCGA) data], has not been investigated to date. In the present study, miR-3677 was revealed to be upregulated in BC as determined using TCGA. miR-3677 was significantly upregulated in BC tissues and cell lines compared with those noted in adjacent non-cancerous tissues and primary normal breast cells (P<0.05). The overexpression of miR-3677 promoted the cell proliferation, migration and invasion of BC cells. Using bioinformatics algorithms and luciferase assays, a novel target gene for miR-3677, namely transducin-like enhancer of Split3 (TLE3), was identified. Silencing of TLE3 in miR-3677-transfected BC cells suppressed their proliferation and migration. An inverse correlation was observed between miR-3677 and TLE3 expression levels in human BC tissues. In conclusion, the present study demonstrated that miR-3677 promoted BC cell proliferation, migration and invasion by inhibiting TLE3 expression, which provided a novel mechanism and a promising therapeutic target for patients with BC.

[Interference of osteopontin expression inhibits the invasion and metastasis of human hepatocellular carcinoma cell lines].

OBJECTIVE: To investigate the effect of osteopontin (OPN) on the invasion and metastasis of human hapatocellular carcinoma (HCC). METHODS: HCC cell lines (HCC-LM3) were transfected with the chemically synthesized small interfering RNA (siRNA). Real-time PCR and Western blot were used to quantify the mRNA and OPN protein levels. The malignant phenotypes including cellular growth, colony formation and invasion capability of the HCC cells were analyzed. RESULTS: The OPN mRNA and proteins levels were decreased by 75% and 80% in OPN siRNA treated cells. Colony formation and migratory capability were reduced in OPN siRNA treated cells (P < 0.05). CONCLUSION: The specific siRNA is able to reduce the OPN expression at both the mRNA and protein levels and significantly inhibits the invasiveness of HCC cells.

[Influence of liver regeneration after partial hepatectomy on the development of liver metastasis of colon cancer in rats].

OBJECTIVE: To investigate the stimulated effect of liver regeneration on colon cancer cells in remnant liver in rats. METHODS: Rat models with liver metastases or retro-peritoneal metastases of colon cancer were established: animals underwent 37% or 70% liver resection and were compared with a sham laparotomy (15, 25, 15 cases, respectively). Metastases were performed two weeks before resection. Rats were killed 3 weeks after the resection. Total body weight, liver and tumor weights were recorded. The human colon adenocarcinoma cell line Lovo was cultured in the presence of portal serum withdrawn 24 hours and 14 days after partial hepatectomy (PH). DNA synthesis was assessed by flow cytometry analysis for 5-Bromodeoxyuridine (5-BrdU) incorporation. RESULTS: The tumor growth was accelerated in the remnant liver in 70% PH group, but the tumors in 37% PH group and retro-peritoneal site were not influenced by PH. Compared with the control group, after cultured 72 hours with portal serum withdrawn 24 h after PH, a higher 5-BrdU incorporation was found in the Lovo cell lines (P < 0.05), and it reached the peak after 120 hours of culture (P < 0.05). No difference was found between the groups when cultured with the portal serum withdrawn 14 d after PH (P > 0.05). CONCLUSIONS: PH may accelerate the growth of residual microscopic tumor in the liver which contributes to local recurrence. It has no systemic effect and effects on the cancer cell lines in extrahepatic sites. The excision extension is related to the stimulating effects on the cancer cell line, and subtotal hepatectomy is presumably a major determinant.

[The roles of caveolin-1 and endothelial nitric oxide synthase in the development of portal hypertension in rats with liver cirrhosis].

OBJECTIVE: To study the relationship between the dynamic changes of caveolin-1 with the degrees of liver fibrosis and portal venous pressure (PVP) in the process of rat liver cirrhosis formation induced by dimethylnitrosamine (DMN); also to investigate the mechanisms of caveolin-1 in the regulation of endothelial nitric oxide synthase (eNOS). METHODS: Liver cirrhosis was induced in rats by DMN. The degrees of liver fibrosis and PVP were measured. NOS activity was assessed by citrulline generation. Protein expressions of caveolin-1, eNOS and caveolin-1-eNOS interactions were examined by Western blot and immunoprecipitation, respectively. RESULTS: Four weeks after DMN administration, liver fibrosis was at its peak and then decreased gradually. Immunoprecipitation and Western blot demonstrated that there was enhanced binding of caveolin-1 with eNOS in the process of rat liver cirrhosis. An increase in caveolin-1 expression was detected but the expression of eNOS was lower in cirrhotic tissues than in normal liver tissues. Caveolin-1 protein levels were positively correlated with the degrees of liver fibrosis and the levels of PVP (r=0.967, P < 0.01; r=0.922, P < 0.01, respectively), while NOS catalytic activity was negatively correlated with the degrees of liver fibrosis and levels of PVP (r= 0.973, P < 0.01; r=-0.947, P < 0.01) respectively. CONCLUSIONS: Caveolin-1 upregulation is associated with the development of portal hypertension in liver cirrhosis. Over-expression of caveolin-1 in perisinusoidal cells may promote caveolin-1-eNOS binding and reduce the activity of eNOS.

Long non-coding RNA SPRY4-IT1 pormotes colorectal cancer metastasis by regulate epithelial-mesenchymal transition.

Colorectal cancer (CRC) remains one of the most common cancers worldwide. Increasing evidence indicates that SPRY4 intronic transcript 1 (SPRY4-IT1) regulate cell growth, differentiation, apoptosis, and cancer progression. However, the expression and function of SPRY4-IT1 in the progression of CRC remains largely unknown. Here, we reported that SPRY4-IT1 was upregulated in CRC. Increased SPRY4-IT1 expression in CRC was associated with larger tumor size and higher clinical stage. In vitro experiments revealed that SPRY4-IT1 knockdown significantly inhibited CRC cell proliferation by causing G1 arrest and promoting apoptosis, whereas SPRY4-IT1 overexpression promoted cell proliferation. Further functional assays indicated that SPRY4-IT1 overexpression significantly promoted cell migration and invasion by regulate the epithelial-mesenchymal transition (EMT). Taken together, our study demonstrates that SPRY4-IT1 could act as a functional oncogene in CRC, as well as a potential therapeutic target to inhibit CRC metastasis.

MiR-639 promoted cell proliferation and cell cycle in human thyroid cancer by suppressing CDKN1A expression.

Accumulating evidence has indicated that aberrantly expressed microRNAs (miRs) are extensively involved in cancer development and progression. MiR-639 has been reported to act as tumor promoter in various types of cancer. However, the biological function and underlying molecular mechanism of miR-639 in thyroid carcinoma (TC) have not been intensively investigated. Herein the present study aimed to investigate the functional role of miR-639 in TC. We found that miR-639 expression was upregulated in TC cells and clinical tissues. Overexpression of miR-639 promoted TC cell proliferation and cell cycle, with increased expression of CyclinE and c-myc, whereas miR-639-in reverses the function. Using prediction software and luciferase reporter assay, we found that CDKN1A was a target of miR-639. CDKN1A small interfering RNA (siRNA) abrogated the role of miR-639-in on cell proliferation of TC. In summary, our data demonstrated that miR-639 upregulation was associated with development of TC, miR-639 promoted cell proliferation and cell cycle by targeting CDKN1A in TC.

The Association Between Serum Levels of Selenium, Copper, and Magnesium with Thyroid Cancer: a Meta-analysis.

There are conflicting reports on the correlation between serum levels of selenium (Se), copper (Cu), and magnesium (Mg) with thyroid cancer. The purpose of the present study is to clarify the association between Se, Cu, and Mg levels with thyroid cancer using a meta-analysis approach. We searched articles indexed in PubMed published as of January 2015 that met our predefined criteria. Eight eligible articles involving 1291 subjects were identified. Overall, pooled analysis indicated that subjects with thyroid cancer had lower serum levels of Se and Mg, but higher levels of Cu than the healthy controls [Se: standardized mean difference (SMD) = -0.485, 95% confidence interval (95%CI) = (-0.878, -0.092), p = 0.016; Cu: SMD = 2.372, 95%CI = (0.945, 3.799), p = 0.001; Mg: SMD = -0.795, 95%CI = (-1.092, -0.498), p < 0.001]. Further subgroup analysis found lower serum levels of Se in thyroid cancer in Norway [SMD = -0.410, 95%CI = (-0.758, -0.062), p = 0.021] and Austria [SMD = -0.549, 95%CI = (-0.743, -0.355), p < 0.001], but not in Poland (SMD = -0.417, 95%CI = (-1.724, 0.891), p = 0.532]. Further subgroup analysis also found that patients with thyroid cancer had higher serum levels of Cu in China [SMD = 1.571, 95%CI = (1.121, 2.020), p < 0.001] and Turkey [SMD = 0.977, 95%CI = (0.521, 1.432), p < 0.001], but not in Poland [SMD = 3.471, 95%CI = (-0.056, 6.997], p = 0.054]. In conclusion, this meta-analysis supports a significant association between serum levels of Se, Cu, and Mg with thyroid cancer. However, the subgroup analysis found that there was significant effect modification of Se, Cu levels by ethnic, like China and Poland. Thus, this finding needs further confirmation by a trans-regional multicenter study to obtain better understanding of causal relationship between Se, Cu, and Mg with thyroid cancer of different human races or regions.

The association between deficient manganese levels and breast cancer: a meta-analysis.

There are conflicting reports on the correlation between manganese (Mn) levels and breast cancer. The purpose of the present study is to clarify the association between Mn levels and breast cancer using a meta-analysis approach. We searched articles indexed in Pubmed and the Chinese Journal Full-text Database (CJFD) published as of August 2014 that met our predefined criteria. Eleven eligible studies involving 1302 subjects were identified. Overall, pooled analysis indicated that subjects with breast cancer had lower Mn levels than the healthy controls (SMD = -1.51, 95% CI = [-2.47, -0.56]). Further subgroup analysis found a similar pattern in China (SMD = -1.32, 95% CI = [-2.33, -0.32]) and Korea (SMD = -4.08, 95% CI = [-4.63, -3.54]), but not in Turkey (SMD = -0.96, 95% CI = [-3.19, 1.27]). Further subgroup analysis also found a similar pattern in different sample specimens (serum: SMD = -1.24, 95% CI = [-2.31, -0.16]; hair: SMD = -1.99, 95% CI = [-3.91, -0.06]) and different types of Mn measurement (inductively coupled plasma-atomic absorption spectrometry (ICP-AAS): SMD = -1.14, 95% CI = [-2.24, -0.04]; graphite furnace atomic absorption spectroscopy (GFAAS): SMD = -1.94, 95% CI = [-2.38, -1.49]; inductively coupled plasma-atomic emission spectrometry (ICP-AES): SMD = -3.77, 95% CI = [-4.70, -2.85]). No evidence of publication bias was observed. In conclusion, this meta-analysis supports a significant association between deficient Mn levels and breast cancer. However, the subgroup analysis found that there was contradiction regarding races and geography, like China and Turkey. Thus this finding needs further confirmation by trans-regional multicenter, long-term observation in a cohort design to obtain better understanding of causal relationships between Mn levels and breast cancer, through measuring Mn at baseline to investigate whether the highest Mn category versus lowest was associated with breast cancer risk.