Abnormal blood levels of trace elements and metals, DNA damage, and breast cancer in the state of Kuwait

Serum Levels of Copper and Zinc and Survival in Breast Cancer Patients

There is emerging interest in the relationship between several serum micronutrients and the prognosis of patients with breast cancer. The relationship between serum zinc and copper levels and breast cancer prognosis is unclear. In our study, we included 583 patients with breast cancer diagnosed between 2008 and 2015 in the region of Szczecin, Poland. In a blood sample obtained before treatment, serum zinc and copper levels were quantified by mass spectroscopy. Each patient was assigned to one of four categories (quartiles) based on the distribution of the elements in the entire cohort. Patients were followed from diagnosis to death over a mean of 10.0 years. The 10-year overall survival was 58.3% for women in the highest and 82.1% for those in the lowest quartile of serum copper/zinc ratio (p < 0.001). The multivariate hazard ratio (HR) for breast cancer death was 2.07 (95% CI 1.17-3.63; p = 0.01) for patients in the highest quartile of serum copper/zinc ratio compared to those in the lowest. There is evidence that the serum zinc level and copper/zinc ratio provide an independent predictive value for overall survival and breast cancer-specific survival after breast cancer diagnosis.

Regulatory roles of copper metabolism and cuproptosis in human cancers

Copper is an essential micronutrient for human body and plays a vital role in various biological processes including cellular respiration and free radical detoxification. Generally, copper metabolism in the body is in a stable state, and there are specific mechanisms to regulate copper metabolism and maintain copper homeostasis. Dysregulation of copper metabolism may have a great connection with various types of diseases, such as Wilson disease causing copper overload and Menkes disease causing copper deficiency. Cancer presents high mortality rates in the world due to the unlimited proliferation potential, apoptosis escape and immune escape properties to induce organ failure. Copper is thought to have a great connection with cancer, such as elevated levels in cancer tissue and serum. Copper also affects tumor progression by affecting angiogenesis, metastasis and other processes. Notably, cuproptosis is a novel form of cell death that may provide novel targeting strategies for developing cancer therapy. Copper chelators and copper ionophores are two copper coordinating compounds for the treatment of cancer. This review will explore the relationship between copper metabolism and cancers, and clarify copper metabolism and cuproptosis for cancer targeted therapy.

Association of Gut Microbiota Enterotypes with Blood Trace Elements in Women with Infertility

Infertility is defined as failure to achieve pregnancy within 12 months of unprotected intercourse in women. Trace elements, a kind of micronutrient that is very important to female reproductive function, are affected by intestinal absorption, which is regulated by gut microbiota. Enterotype is the classification of an intestinal microbiome based on its characteristics. Whether or not Prevotella-enterotype and Bacteroides-enterotype are associated with blood trace elements among infertile women remains unclear. The study aimed to explore the relationship between five main whole blood trace elements and these two enterotypes in women with infertility. This retrospective cross-sectional study recruited 651 Chinese women. Whole blood copper, zinc, calcium, magnesium, and iron levels were measured. Quantitative real-time PCR was performed on all fecal samples. Patients were categorized according to whole blood trace elements (low levels group, <5th percentile; normal levels group, 5th‒95th percentile; high levels group, >95th percentile). There were no significant differences in trace elements between the two enterotypes within the control population, while in infertile participants, copper (P = 0.033), zinc (P < 0.001), magnesium (P < 0.001), and iron (P < 0.001) in Prevotella-enterotype was significantly lower than in Bacteroides-enterotype. The Chi-square test showed that only the iron group had a significant difference in the two enterotypes (P = 0.001). Among infertile patients, Prevotella-enterotype (Log(P/B) > −0.27) predicted the low levels of whole blood iron in the obesity population (AUC = 0.894; P = 0.042). For the high levels of iron, Bacteroides-enterotype (Log(P/B) <−2.76) had a predictive power in the lean/normal group (AUC = 0.648; P = 0.041) and Log(P/B) <−3.99 in the overweight group (AUC = 0.863; P = 0.013). We can infer that these two enterotypes may have an effect on the iron metabolism in patients with infertility, highlighting the importance of further research into the interaction between enterotypes and trace elements in reproductive function.

Serum trace element levels of gastrointestinal cancer patients in an endemic upper gastrointestinal cancer region

Gastrointestinal (GI) cancers are an important cause of the death rate in Turkey and in the world. Especially upper (esophageal and gastric) GI cancers are the leading types of cancer by 20-27% in Eastern Turkey. Trace elements are involved in many physiological and metabolic processes in the human body. Recent studies suggest that the increase or decrease of trace elements in the body may be related to the formation and development of many diseases such as cancers, diabetes mellitus and cardiovascular diseases etc. METHOD AND MATERIALS: In this study some trace elements; cadmium (Cd), cobalt (Co), Copper (Cu), iron (Fe), magnesium (Mg), manganese (Mn), nickel (Ni), lead (Pb), zinc (Zn) concentrations were investigated in the blood serums of esophageal, gastric and colon cancer patients and healthy controls in Van city area, an endemic upper (esophageal and gastric) GI region of Eastern Turkey. The analysis of the elements was realized with a flame atomic absorption spectrophotometer (FAAS). RESULTS: Mean serum levels of Cd and Ni in esophageal and gastric cancer patients were very significantly lower compared to controls (p < 0.001 and < 0.005). In addition, the mean serum Co level of esophageal cancer patients was very significantly lower than in controls and gastric cancer patients (p < 0.002). Also, the mean serum levels of Fe and Mn in all (esophageal, gastric and colon) cancer groups were very significantly lower than in controls (p < 0.001 and 0.002). Mean serum levels of Cu, Mg, Pb and Zn were not significantly different in all cancer patients compared to controls. CONCLUSION: We have detected the deficiency of five trace elements (Fe, Mn, Cd, Ni, Co) in esophageal, gastric and colon cancer patients. The deficiencies of trace elements may be due to malign over consumption of the nutrients and to the malnutrition of the advanced cancer patients. Nutritional therapy rich in trace elements should be considered as one of the strategies to fight against cancers.

Relationships Between Biological Heavy Metals and Breast Cancer: A Systematic Review and Meta-Analysis

Introduction

Heavy metals were classified as essential, probably essential, and potentially toxic in the general population. Until now, it has been reported inconsistently on the association between heavy metals and BC. In this meta-analysis, we aimed to assess the association between heavy metals and BC and review the potential mechanisms systematically.

Methods

We searched for epidemiological studies in English about the association between heavy metals and BC published before September 2020 in PubMed, Web of Science, and Embase databases. In total 36 studies, comprising 4,151 individuals from five continents around the world were identified and included.

Results

In all biological specimens, Cu, Cd, and Pb concentrations were higher, but Zn and Mn concentrations were lower in patients with BC than in non-BC participants [SMD (95% CIs): 0.62 (0.12, 1.12); 1.64 (0.76, 2.52); 2.03 (0.11, 3.95); −1.40 (−1.96, −0.85); −2.26 (−3.39, −1.13); p = 0.01, 0.0003, 0.04, <0.0001, <0.0001]. Specifically, higher plasma or serum Cu and Cd, as well as lower Zn and Mn, were found in cases [SMD (95% CIs): 0.98 (0.36, 1.60); 2.55 (1.16, 3.94); −1.53 (−2.28, −0.78); −2.40 (−3.69, −1.10); p = 0.002, 0.0003, <0.0001, 0.0003]; in hair, only lower Zn was observed [SMD (95% CIs): −2.12 (−3.55, −0.68); p = 0.0004]. Furthermore, the status of trace elements probably needs to be re-explored, particularly in BC. More prospective studies, randomized clinical trials, and specific pathogenic studies are needed to prevent BC. The main mechanisms underlying above-mentioned findings are comprehensively reviewed.

Conclusion

For BC, this review identified the current knowledge gaps which we currently have in understanding the impact of different heavy metals on BC.

Systematic Review Registration

www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42020176934, identifier: CRD42020176934.

Evaluation of the influence of diet supplementation with conjugated linoleic acid isomers on elemental composition in the cardio-oncological nutritional programming rat' model

BACKGROUND

The 'developmental origin of health and disease' (DOHaD) hypothesis assumes that due to the action of some stimuli during fetal life the long-term physiological changes occurs and may affects the risk of various diseases. The main aim of this study was to assess impact of supplementation of maternal' and early postnatal diet with conjugated linoleic acids (CLA) isomers on selected elements content in hearts of their female offspring with chemically induced breast cancer.

METHODS

Elemental composition was determined by quadrupole mass spectrometer with inductively coupled plasma ionization (ICP-MS).

RESULTS

The effect of maternal' diet on the elements content was more pronounced than the progeny diet modifications. Significant correlations among determined elements, especially macroelements, and lipidomic parameters, in the experimental factors dependent manner were observed. It can be concluded that supplementation of maternal and progeny diets with CLA isomers may significantly influence the contents of both macro- and microelements in cardiac tissue of newborns.

CONCLUSION

Our results also indicate, that dynamic and intricate balance among various elements in body may be affected by the lipid dietary supplements also in the pathological state. Utility of cardio-oncological approach in developmental programming study was confirmed.

Cancer Influences the Elemental Composition of the Myocardium More Strongly than Conjugated Linoleic Acids-Chemometric Approach to Cardio-Oncological Studies

The aim of the study was to verify in a cardio-oncological model experiment if conjugated linoleic acids (CLA) fed to rats with mammary tumors affect the content of selected macro- and microelements in their myocardium. The diet of Sprague-Dawley females was supplemented either with CLA isomers or with safflower oil. In hearts of rats suffering from breast cancer, selected elements were analyzed with a quadrupole mass spectrometer with inductively coupled plasma ionization (ICP-MS). In order to better understand the data trends, cluster analysis, principal component analysis and linear discriminant analysis were applied. Mammary tumors influenced macro- and microelements content in the myocardium to a greater extent than applied diet supplementation. Significant influences of diet (p = 0.0192), mammary tumors (p = 0.0200) and interactions of both factors (p = 0.0151) were documented in terms of Fe content. CLA significantly decreased the contents of Cu and Mn (p = 0.0158 and p = 0.0265, respectively). The level of Ni was significantly higher (p = 0.0073), which was more pronounced in groups supplemented with CLA. The obtained results confirmed antioxidant properties of CLA and the relationship with Se deposition. Chemometric techniques distinctly showed that the coexisting pathological process induced differences to the greater extent than diet supplementation in the elemental content in the myocardium, which may impinge on cardiac tissue's susceptibility to injuries.

Serum copper and zinc levels in breast cancer: A meta-analysis

BACKGROUND

More and more studies have investigated the relationship between serum copper (Cu) and/or zinc (Zn) levels and breast cancer (BC). However, the results are inconsistent. It is unclear whether the serum Cu to Zn ratio (Cu/Zn) is associated with BC risk. Therefore, we evaluated serum Cu and Zn concentrations, and Cu/Zn in BC through meta-analysis.

MATERIALS AND METHODS

Studies reporting serum Cu and/or Zn concentrations in BC patients and controls from 1991 to 2020 were identified from PubMed, CNKI, and Wanfang databases online. Based on a random effects model, summary standard mean differences (SMDs) and the corresponding 95 % confidence intervals (95 % CIs) were applied to compare the serum levels of Cu, Zn and Cu/Zn between BC patients and controls.

RESULTS

Thirty-six eligible studies involving 5747 female subjects were included. The present study illustrated that the BC patients had significantly higher serum Cu levels than healthy controls (HC) (SMD (95 % CI): 1.99(1.48, 2.49)) and patients with benign breast diseases (BD) (SMD (95 % CI): 0.99(0.38, 1.61)). However, Zn concentrations were statistically decreased in BC patients than HC (SMD (95 % CI): -1.20(-1.74, -0.66)) and BD (SMD (95 % CI): -1.13 (-1.73, -0.54)). Cu/Zn concentrations were remarkably increased in BC patients than HC (SMD (95 % CI): 2.75(1.79, 3.60)) and BD (SMD (95 % CI): 2.98(1.91, 4.05)) in some studies.

CONCLUSION

The results show that elevated serum levels of Cu and Cu/Zn, as well as decreased Zn might be associated with increased risk of breast cancer. These three parameters have the potential to distinguish breast cancer from benign breast diseases.

Correlations between 13 Trace Elements and Circulating Tumor Cells in Patients with Colorectal Cancer in Guangzhou, China

We established a method of determining 13 trace elements (TEs) in whole blood, determined the levels of the TEs in patients with colorectal cancer (CRC), and examined the correlations between the TEs and circulating tumor cells (CTCs). A total of 93 CRC patients and 48 control subjects in Guangzhou, China, were included. Inductively coupled plasma mass spectrometry (ICP-MS) was used to measure the blood levels of 13 TEs. CTCs of 13 CRC patients were examined using CanPatrol™. The levels of Mg, Fe, Zn, Se, Sr, Mo, and Ba in CRC patients were lower than those in control subjects (all, P < 0.05). The levels of Mg, Fe, Zn, Se, and Ba decreased with increasing TNM stage. The reductions of Zn and Se levels were higher in early-stage than late-stage CRC patients. The levels of Cu and Ni were higher in CRC patients than in control subjects (both, P < 0.05). The Cu level increased with increased TNM stage, and Ni level was higher in early-stage CRC patients as compared with late-stage CRC patients. Consequently, the TE levels showed differences as the process of TNM stage of CRC patients. There were correlations between the amount of CTCs and epithelial-CTCs (E-CTCs) and interstitial-CTCs (M-CTCs) (P < 0.05). The levels of Mg, Cr, Fe, Cu, Zn, Se, Sr, and Ba were correlated with the number of CTCs (P < 0.05). Specific TE patterns in whole blood may assist in the early diagnosis of CRC. The combined determination of TE levels and CTCs may be useful as an adjunct to staging and guiding treatments.

Copper mediates mitochondrial biogenesis in retinal pigment epithelial cells

Age related macular degeneration (AMD) is a multifactorial disease with genetic, biochemical and environmental risk factors. We observed a significant increase in copper levels in choroid-RPE from donor eyeballs with AMD. Adult retinal pigment epithelial cells (ARPE19 cells) exposed to copper in-vitro showed a 2-fold increase in copper influx transporter CTR1 and copper uptake at 50 μM concentration. Further there was 2-fold increase in cytochrome C oxidase activity and a 2-fold increase in the mRNA expression of NRF 2 with copper treatment. There was a significant increase in mitochondrial biogenesis markers PGC1β and TFAM which was confirmed by mitochondrial mass and copy number. On the contrary, in AMD choroid-RPE, the CTR1 mRNA was found to be significantly down-regulated compared to its respective controls. SCO1 and PGC1β mRNA showed an increase in choroid-RPE. Our study proposes copper to play an important role in mitochondrial biogenesis in RPE cells.

Assessment of Serum CoQ10 Levels and other Antioxidant Markers in Breast Cancer

BACKGROUND

The balance of the oxidative state in the body is fundamental for the maintenance of homeostasis. It has been implicated in the onset and progression of several diseases including breast cancer. The way in which the Reactive Oxygen Species (ROS) / antioxidants balance leads to or responds to disease is still controversial. In this study, TAC is used as a reference for the total antioxidant power of the body and Coenzyme Q10 (CoQ10) for its vital importance in cellular antioxidant action and being the only lipid soluble antioxidant synthesized endogenously. Copper and zinc were measured as trace elements reflecting the antioxidant micronutrient profile of the body.

METHODS

After approval of the ethical committee, 60 recently diagnosed non-intervened breast cancer patients were recruited from the Medical Research Institute hospital, Alexandria University along with 20 apparently healthy volunteers as control group. Full patient history was taken including breastfeeding history, parity, hormone replacement therapy use, body mass index, pathological examination, metastatic work up results, past medical history and drug use. CA 15-3 and laboratory investigations evaluating blood glucose, kidney and liver functions were performed. Q10 levels were measured by HPLC using a kit from Recipe®. TAC was assayed spectrophotometrically (Biodiagnostics®). Copper and Zinc levels were determined by inductively coupled plasma-optical emission spectrometry.

RESULTS

There was a statistically significant increase in the CoQ10, TAC and copper levels in the breast cancer group when compared to the control group. Zinc showed no statistically significant difference between the studied groups.

CONCLUSION

Inspite of the fact that a high antioxidant level is usually considered as a favourable state, TAC, CoQ10 and copper levels showed significantly higher levels in the breast cancer group when compared to the control group. It is worth mentioning that the cancer group were all recently diagnosed, non-intervened and showed no signs of metastasis. It is still unclear whether the increased antioxidant levels offer a selective growth advantage to tumor cells over their surrounding normal cells or serve as a protective measure by the body in an attempt to correct the assault triggered by the ROS.

A meta-analysis of zinc levels in breast cancer

BACKGROUND

Breast cancer is the most commonly occurring neoplasm in females, comprising 16% of all female cancers worldwide. Various studies indicate some discrepancies regarding zinc (Zn) levels in various samples of breast cancer patients.

OBJECTIVE

The present study evaluated by meta-analysed the published data for Zn levels analyzed in breast tissue, plasma, serum, and hair samples and its relationship with breast cancer.

METHODS

The present meta-analysis included 36 studies, all of which were published in the years between 1984 to 2017 and selected by searching the databases MEDLINE, EMBASE, Cochrane Library, PubMed, Scopus, and the ISI Web of Knowledge. The articles were analyzed, and I² statistics were used to examine heterogeneity. The objective analysis was performed on data from the 36 studies, with total 1699 study subjects and 2009 controls.

RESULTS

Significant statistical differences overall were observed, based on a random effects model (SMD (95 % CI), -0.78[-1.40, -0.16], P = 0.014). Data from 19 of these studies indicated significant statistical differences between cancerous patients and controls with regard to serum and plasma Zn concentration (SMD [(95 %CI): -1.61(-2.43, -0.79)]. There was a significant statistical difference between the breast tissue and hair as regards Zn status (SMD (95%CI): 2.32(1.42, 3.21)) and (SMD (95v%CI): -1.80(-3.41, -0.20), respectively. Zn concentration levels typically decreased in blood and hair samples of patients with breast cancer, whereas it was elevated in tumor tissues.

CONCLUSIONS

There is a significant relationship between lowered serum Zn concentrations and risk of breast cancer onset or recurrences in women, but because of high heterogeneity, we recommend other primary studies.

Serum Trace Elements and Their Associations with Breast Cancer Subgroups in Korean Breast Cancer Patients

The relationships between serum levels of trace elements and breast cancer remain relatively unknown. In this study, we investigate serum levels of seven trace elements in Korean breast cancer patients compared to controls without breast cancer. Serum trace element levels were determined using inductively coupled plasma mass spectrometry in Korean breast cancer patients before initiation of breast cancer treatment. Korean females without breast cancer served as a control group. Trace element levels were measured in the discovery cohort (n = 287) and were validated in an independent cohort (n = 142). We further investigated possible associations between trace element levels and the presence of lymph node metastasis, distant metastasis, or triple-negative breast cancer among breast cancer patients in subgroup analyses. Serum manganese and molybdenum levels were significantly higher (p < 0.05) in breast cancer patients than in controls. Serum copper levels were significantly higher in breast cancer patients with distant metastasis, while selenium levels were significantly lower. Other trace elements were neither significantly different between breast cancer patients and controls nor between subgroups of breast cancer patients. Our study provides insights about the potential roles and impacts of trace elements through an assessment of the associations between trace elements and breast cancer.

Serum and whole blood Zn, Cu and Mn profiles and their relation to redox status in lung cancer patients

Disturbed redox status may be critical to lung cancerogenesis, however little research has been conducted on general changes in total redox status in lung cancer. Levels and activities of antioxidants, especially enzymatic ones, are related to trace element concentration. Trace element status is often disturbed in cancers, however no studies concerning the association between redox and trace element status have been performed for lung cancer. We hypothesized that disturbed redox status in lung cancer patients is partially determined by trace elements while their distribution amongst blood compartments may differ compared to healthy subjects. Blood samples from lung cancer patients (n=44) and control subjects (n=44) were collected to assess redox and trace element status. Serum and whole blood Cu and Mn levels were determined with GF-AAS, and Zn-with F-AAS. In serum the total antioxidant status (TAS) was determined with the commercial kit TAS (Randox, UK), total oxidant status (TOS) was determined based on the method developed by Erel and the oxidative stress index (OSI) was calculated. Total protein (T-Prot), albumin (Alb), uric acid (UA) and total bilirubin (T-Bil) concentrations were measured with an auto-analyser (Konelab 20i, Thermoscientific, USA), SOD and CAT activity - with commercially available kits (Cayman, USA). The level of TAS, T-Prot, Alb, T-Bil, the activity of SOD, the concentration of whole blood Mn as well as serum and whole blood Zn were lower while TOS, OSI, serum Cu levels and serum Cu:Zn ratios were higher in lung cancer patients compared to the control group. In the lung cancer group TAS correlated positively with Alb and UA, serum Zn and negatively with whole blood Mn. Additionally, SOD positively correlated with the whole blood Mn and Cu:Zn ratio, while CAT - negatively with the whole blood Cu:Zn ratio. In the lung cancer sub-group at clinical stage I-II, TOS additionally negatively correlated with whole blood Zn, and CAT negatively with serum Cu and Cu:Zn ratio. In advanced lung cancer, we found a positive correlation between TAS and serum Zn, and a negative one - with serum Cu:Zn ratio. We observed a similar correlation between endogenous non-enzymatic antioxidants and TAS in the control group, however considerably fewer correlations between trace elements and antioxidants were observed. This study supports the hypothesis that disturbed redox status in lung cancer patients is linked with alterations in trace element status regarding Zn, Mn and Cu. Moreover, the type of biological fluid influences both - alterations in the metal profile and relationships with redox status parameters.

State of the evidence 2017: an update on the connection between breast cancer and the environment

BACKGROUND

In this review, we examine the continually expanding and increasingly compelling data linking radiation and various chemicals in our environment to the current high incidence of breast cancer. Singly and in combination, these toxicants may have contributed significantly to the increasing rates of breast cancer observed over the past several decades. Exposures early in development from gestation through adolescence and early adulthood are particularly of concern as they re-shape the program of genetic, epigenetic and physiological processes in the developing mammary system, leading to an increased risk for developing breast cancer. In the 8 years since we last published a comprehensive review of the relevant literature, hundreds of new papers have appeared supporting this link, and in this update, the evidence on this topic is more extensive and of better quality than that previously available.

CONCLUSION

Increasing evidence from epidemiological studies, as well as a better understanding of mechanisms linking toxicants with development of breast cancer, all reinforce the conclusion that exposures to these substances - many of which are found in common, everyday products and byproducts - may lead to increased risk of developing breast cancer. Moving forward, attention to methodological limitations, especially in relevant epidemiological and animal models, will need to be addressed to allow clearer and more direct connections to be evaluated.

Cadmium exposure and the risk of breast cancer in Chaoshan population of southeast China

Recently, there is increasing evidence indicating a link between cadmium exposure and human breast cancer. This study was aimed to explore the relationship between blood cadmium burden and the risk of breast cancer in Chaoshan women with no occupational exposure. Blood cadmium levels (BCLs) were determined in whole blood of 186 breast cancer cases and 139 controls. Basic clinical data and information of age, occupation, blood types, family cancer history, and disease history, as well as other demographic characteristics were collected from medical records. BCLs were detected by graphite-furnace atomizer absorption spectrophotometer (GFAAS). BCLs and proportions of BCLs over 3 μg/L between cases and controls were compared. The relationships between BCLs and breast cancer were explored by comparing BCL differences between/among different characteristics of investigated factors. In addition, BCLs within cases were also compared in relation to the disease clinical stages, tumor-node-metastasis (TNM) stages, and estrogen receptor (ER), progesterone receptor (PR), and Cerb-B2 expressions. The breast cancer patients had a higher median concentration of blood cadmium (2.28, interquartile range 1.57-3.15 μg/L) than the controls (1.77, 1.34-2.57 μg/L; P = 0.001). The proportion of BCLs over 3 μg/L was 2.35 times higher in the breast cancer cases than that of the controls after adjusting for age. Cadmium tends to accumulate in the human body with age and body mass index (BMI) but not associates with type of job, family history, disease history, and other investigated characters. With the increase of clinical stages and T and M stages, the BCLs in the breast cancer cases also increased. BCLs were positively associated with Cerb-B2 expression (r = 0.152, P = 0.038) but not significantly associated with ER and PR expressions. The data obtained show that cadmium concentration is significantly higher in blood of breast cancer patients in comparison to healthy controls. Cadmium seems to be a risk factor of breast cancer, and high cadmium exposure was observed in advanced stages of this disease, which indicates that it may promote the development of breast cancer.

Serum and hair zinc levels in breast cancer: a meta-analysis

Many studies have investigated the association between serum/hair zinc levels and breast cancer, but the results were inconsistent. To compare the serum and hair zinc levels in women with breast cancer and controls, we conducted a systematic literature search of PubMed, Web of Science, Cochrane Library and Embase to identify relevant studies with publication dates up through November 2014. Based on a random effects model, summary standard mean differences (SMDs) and the corresponding 95% confidence intervals (CIs) were used to compare the serum and hair zinc levels in women with breast cancer and controls. Fourteen studies that investigated serum zinc levels and seven studies that assessed hair zinc levels were included. Our study observed no difference in serum zinc levels between breast cancer cases and controls (SMD (95%CI): -0.65[-1.42, 0.13]). However, we determined that hair zinc levels were lower in women with breast cancer compared with those of controls (SMD (95%CI): -1.99[-3.46, -0.52]). In conclusion, this study was the first to provide evidence that hair zinc levels in female breast cancer patients are lower than in controls; however, there was no significant difference in serum zinc levels between female breast cancer patients and controls.

Analysis of serum levels of 15 trace elements in breast cancer patients in Shandong, China

Experimental and epidemiological studies suggest that serum levels of trace elements may be associated with breast cancer risk. We compared serum levels of 15 trace elements between breast cancer patients and normal controls from Shandong, China, for the first time to assess whether serum levels of trace elements were associated with breast cancer risk. Eighty-eight breast cancer patients and 84 healthy controls were enrolled in the study. A Spectraspan V direct current plasma atomic emission spectrometer was used to determine the serum levels of 15 trace elements including Zn, Mn, Al, Cd, Fe, Mg, Ca, Pb, Cu, Se, Ni, Ti, Co, Li, and Cr. Breast cancer patients had significantly higher serum levels of Cd (p = 0.000), Mg (p = 0.001), Cu (p = 0.000), Co (p = 0.006), and Li (p = 0.003) and borderline higher Cr (p = 0.052), while significantly lower Mn (p = 0.000), Al (p = 0.000), Fe (p = 0.000), and Ti (p = 0.000) compared to their matched controls. However, there were no significant differences in serum levels of Zn (p = 0.824), Ca (p = 0.711), Pb (p = 0.274), Se (p = 0.236), and Ni (p = 0.185) between the two groups. Our study showed a possible association between serum levels of trace elements and breast cancer risk in eastern China, though it warrants further investigations to confirm the association. If confirmed, modulation of trace elements may help reduce breast cancer risk.

Impact of trace element changes on dehydroepiandrosterone sulfate in healthy and diabetic states among middle-age and elderly Egyptians

The aim of this study was to confirm if there is a link between the alteration in blood levels of trace elements (chromium, copper, lead, cadmium, and zinc) and dehydroepiandrosterone sulfate (DHEAS) in healthy and diabetic states. This study is the first study to test these parameters in Egyptians. The study included 150 subjects divided into the following four groups: healthy middle-aged, healthy elderly, middle-aged diabetics, and elderly diabetics. Our results revealed a statistically significant decrease in the level of DHEAS in the elderly compared to middle-aged healthy and diabetic groups (p < 0.05). There was a significant difference between the middle-aged groups with respect to zinc, copper, chromium, and cadmium levels. Zinc and copper were lower in the diabetic subjects while chromium and cadmium were higher in the same group in comparison to healthy subjects. In the elderly groups, there were significant increases in chromium and cadmium levels in diabetic subjects rather than healthy ones. There was a significant increase in the thiobarbituric acid reactive substance level in the elderly healthy and diabetic groups and a significant decrease in the glutathione level in the elderly groups. There was no correlation between the levels of trace elements and DHEAS or between the levels of DHEAS, oxidants, and antioxidants in all of the tested groups. In conclusion, only the DHEAS level was correlated with age. There was no difference between the diabetic and healthy groups with respect to the levels of trace elements, with the exception of chromium and cadmium, which suggests the effect of pollution on the pathogenesis of diabetes in Egyptians. No correlation existed between the levels of DHEAS and trace elements, oxidants, and antioxidants. Finally, we believe that there is a large regional variation in the levels of trace elements due to different environmental exposure and nutritional factors which are responsible for contradictory results regarding the pathogenesis of diseases related to alterations in the levels of trace elements.

Metals and breast cancer: risk factors or healing agents?

Metals and metal compounds are part of our environment. Several metals are essential for physiological functions (e.g., zinc or magnesium); while the beneficial effects of others are uncertain (e.g., manganese), some metals are proven to be toxic (e.g., mercury, lead). Additionally there are organic metal compounds; some of them are extremely toxic (e.g., trimethyltin, methylmercury), but there is very little knowledge available how they are handled by organisms. Scientific evidence indicates that long-term exposure to (some) metallic compounds induces different forms of cancer, including breast cancer. On the other side, several metal compounds have clinical use in treating life-threatening diseases such as cancer. In this paper we discuss the recent literature that shows a correlation between metal exposure and breast cancer.