Zinc and copper in breast cancer. A joint study in northern Italy and southern France

Copper and Melanoma Risk: Results from NHANES 2007-2018 and Mendelian Randomization Analyses

Copper is an essential trace element obtained from food. There is a paucity of observational or prospective studies that have investigated the relationship between copper and melanoma risk. Copper serves as a cofactor for pivotal enzymes involved in mitochondrial respiration, antioxidant defense, and neurotransmitter synthesis. Undoubtedly, copper plays an indispensable role in the initiation and progression of tumors, particularly melanoma; however, further investigations are warranted to elucidate the underlying mechanisms linking copper and melanoma risk. Given the availability of dietary copper and serum copper data in the NHANES database, we conducted an investigation into the association between dietary copper intake and serum copper levels with melanoma risk. We enrolled 26,401 individuals with dietary copper data in the 2007-2018 NHANES database. To mitigate confounding variables, a propensity score matching (PSM) was performed. To assess the association between dietary copper intake and melanoma risk, we employed a multivariate logistic regression analysis before and after PSM. The restricted cubic spline analysis was utilized to determine whether there is a non-linear relationship between dietary copper intake and melanoma risk, with subgroup analysis conducted to determine beneficiaries. Then, those with blood copper data from the enrolled population with dietary copper intake were screened out, and subsequently, multivariate logistic regression models were subsequently constructed to investigate the association between serum copper levels and melanoma risk after PSM. Mendelian analysis was further utilized to validate the results of the NHANES database using serum copper as the exposure factor and melanoma as the outcome variable. The study found that melanoma risk was associated with dietary copper intake before and after PSM, demonstrated by multiple logistic regression. The relationship between dietary copper intake and melanoma risk was non-linear, with a reduced risk observed above approximately 2.5 mg/day, as shown by the RCS. The evidence suggests that an increased intake of copper is linked to a decreased risk of melanoma. To clarify the mechanism behind the increased risk of melanoma due to higher dietary copper intake, we analyzed the population data from the NHANES database on serum copper and dietary copper intake. Our results indicated that there is no causal relationship between serum copper and melanoma risk. Mendelian randomization analysis of multi-database data sources confirmed the conclusion of the NHANES database analysis. Dietary copper is a protective factor against melanoma, and serum copper or blood copper is not associated with melanoma risk. This suggests that serum or blood copper is not responsible for the protective effect of dietary copper intake on melanoma risk, and the mechanisms need to be further investigated.

Dietary Trace Element Intake and Risk of Breast Cancer: A Mini Review

Trace elements are essentially required for various physiological and metabolic functions, and any disturbance in the trace elements homeostasis may result in the development of chronic diseases including breast cancer. Breast cancer is the most prevalent cancer type reported in women equally affecting both the high-income and low-income countries. This review therefore aimed to evaluate the impact of dietary trace element intake in relation to the incidence of breast cancer. We focused on five trace elements, thus emphasizing dietary selenium, zinc, iron, copper, and cadmium intake and risk of breast cancer. A systematic approach was applied to perform this review through entering a search term in PubMed and Scopus databases. A total of 24 articles were included after meeting the inclusion and exclusion criteria. Most of the studies regarding dietary iron intake showed a detrimental effect of increased dietary heme iron on breast cancer incidence risk. In addition, there is a limited evidence of high dietary intake of selenium and zinc to reduce the risk of breast cancer. Also, a few studies showed a relationship between high cadmium consumption and risk of breast cancer. More studies related to cadmium and copper exposure are needed to confirm this relationship. As a result, the findings of this review suggested that high dietary heme iron is a potential risk factor for breast cancer.

Serum zinc and dietary intake of zinc in relation to risk of different breast cancer subgroups and serum levels as a marker of intake: a prospective nested case-control study

PURPOSE

Zinc has been suggested to be protective against breast cancer, but the evidence remains inconclusive. One reason for inconsistent findings in previous studies may be that zinc only influences the risk of developing certain subtypes of breast cancer. Our study is the first study assessing zinc levels in relation to the risk of different breast cancer subgroups, defined by their tumor characteristics. In addition, we analyze serum zinc as a marker of dietary intake.

METHODS

The Malmö Diet and Cancer Study is a population-based cohort study that took place 1991-1996 in Malmö, Sweden. Until end of follow-up, 31 December 2013, 1186 incident cases were identified and matched to an equal number of controls. Odds ratios (ORs) for breast cancer, and having a certain tumor characteristic, were estimated in quartiles of baseline serum zinc and zinc intake and adjusted for potential confounders.

RESULTS

No associations were found between zinc, measured in serum or diet pre-diagnostically, and breast cancer risk. The adjusted OR for breast cancer in serum zinc Q4 compared to Q1 was 1.09 (0.85-1.41) and in zinc intake Q4 versus Q1 was 0.97 (0.77-1.23). Moreover, there were no clear associations between zinc and any breast cancer characteristics. The kappa value, 0.025 (P = 0.022), showed poor agreement between serum zinc and zinc intake.

CONCLUSION

Our findings indicate that there is no clear association between zinc and overall breast cancer risk or risk of different breast cancer subgroups. Finally, our results suggest that serum zinc is a poor marker of zinc intake.

Utilizing molecular resonance-localized surface plasmon resonance coupling for copper ion detection in plasma

The rapid, point-of-care detection of copper in plasma can greatly aid in a large number of diseases where copper has been implicated to be an important factor, such as cancer, Alzheimer's and Diabetes mellitus. Localized surface plasmon resonance (LSPR) technologies show promise in the inexpensive detection of copper, whereas previous platforms are plagued with selectivity and sensitivity issues. Herein, we have created a sensitive and selective on-chip copper sensor which can produce a colorimetric reading in 60 minutes. The selectivity of the assay is based on 'Click' chemistry and is shown to have little interference with other metal ions present in plasma. The sensitivity of the assay is generated from the coupling of the molecular resonance of a dye and the LSPR of the gold nanoparticles. The assay is capable of measuring copper concentrations in human plasma as low as 4 μM and the linear range of sensitivity, 4 to 20 μM, is in the physiologically relevant range. This robust, colorimetric assay should prove useful in a point-of-care setting.

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.

Essential trace elemental levels (zinc, iron and copper) in the biological samples of smoker referent and pulmonary tuberculosis patients

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Smoking is linked with tuberculosis recurrence.

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Pakistan has not only high TB number of TB cases (fifth) but also high level of multidrug-resistant TB (fourth) in the world.

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Cu/Zn ratio was also considerably greater in all biological samples of TB patients as compared to the control group.

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The analysis the levels of the elements, {Fe, Cu, Zn and Cu/Zn ratio} may help the studies on the development of TB disease.

Tuberculosis is one of the major causes of illnesses and deaths throughout world particularly in Asia. Smoking is linked with tuberculosis recurrence and its mortality and may influence bacteriological conversion, clinical symptoms and treatment outcome. The aim of current study was to estimate association among essential trace elements {zinc (Zn), iron (Fe) and copper (Cu)} in human biological samples particularly blood, serum, scalp hair, saliva, sputum, and nasal fluid of smoking and nonsmoking pulmonary tuberculosis patients (n = 165, age ranged 16–35 years) residents of Hyderabad, Pakistan. The biological samples of age matched healthy controls were chosen as referents of both genders (n = 171) for the comparison purpose. The human biological samples were wet digested in microwave oven by 65 % HNO₃ and 30 % H₂O₂ with (2:1) ratio. The concentrations of elements in acid digested samples were determined by atomic absorption spectrometry. The average zinc and iron concentration was lower, while level of copper was higher in the biological samples of pulmonary Tuberculosis patients as compared to referent subjects (p < .001). It was also concluded as a result of Zn and Fe deficiency combined with high contact of copper due to smoking of tobacco can be synergistic with the risk factors related with pulmonary tuberculosis.

Comparative analysis of serum trace element levels in women with invasive cervical cancer in Lagos, Nigeria

Introduction

Trace elements although present in minute quantities in human blood, they play a vital role in many biochemical enzymatic reactions and have been examined critically as a potential key factor in various human diseases including cancers. This study was aimed to determine the association between serum levels of trace elements and invasive cancer of the cervix.

Methods

This was an analytical cross-sectional study carried out among women seen at the Lagos University Teaching Hospital (LUTH). Fifty histologically diagnosed patients with squamous cells carcinoma of the cervix, who had not had any treatment and 100 cancer-free volunteers were recruited. A structured interviewer-administered questionnaire was used to collect relevant data following which venous blood sample was obtained from each participant. Serum zinc, copper and selenium concentrations were then measured. The associations of serum trace elements and invasive cervical cancer were tested using the independent sample t-test. All significances were reported at P<0.05.

Results

There were significantly low serum levels of zinc and selenium in cervical cancer patients with no significant difference seen in the serum level of copper among cervical cancer patients compared to their cancer-free control counterparts.

Conclusion

These alterations in trace elements levels may be important in the pathogenesis of cervical cancers; however, future robust prospective studies are needed to determine if routine provision of these supplements will result in improved cervical cancer treatment outcomes in Nigerian women.

Essential and toxic metals in serum of individuals with active pulmonary tuberculosis in an endemic region

Trace elements play an important role in tuberculosis infection because their deficiencies can be associated with impaired immunity. Blood samples were collected from a total of 320 active pulmonary tuberculosis patients and healthy individuals. The serum concentrations of Zinc, Iron, Copper, Calcium, lead, Arsenic and Selenium were analyzed by atomic absorption spectrometry. The levels of trace elements were measured after 2, 4 and 6 months of anti-TB treatment initiation in TB infected groups. Compared to the control group, the concentrations of Zinc, Selenium, and Iron were significantly lower (P < 0.001) in tuberculosis patients; however, that of Arsenic, Lead, and copper was significantly higher (P < 0.001) in the serum of patients. Cu/Zn and Cu/Se ratios were also significantly higher (P < 0.001) in TB patients compared to the control group. In addition, serum concentration calcium was similar in both TB patients and healthy controls. Our results indicated that trace elements concentrations in tuberculosis patients are related to each element role in immune system. Wherever the element is essential for the pathogenesis of bacteria, its concentration will remain low; and contrariwise, when the element is toxic for the bacteria, its level will be regulated up to provide a perfect condition for bacterial growth.

Levels of Trace Elements in Muscle and Kidney Tissues of Sheep with Fluorosis

In this study, we report the concentrations of four trace elements in muscle and kidney tissues of sheep grown in an area with endemic fluorosis. Fifteen 3- to 4-year-old fluorotic sheep were selected for the study. Ten age-matched sheep with no sign of fluorosis were used as the control group. The animals were killed in a slaughterhouse in the village of Doğubeyazıt, located in the Ağrı province of Eastern Turkey, where kidney and muscle tissue samples were surgically obtained to be analyzed for copper, zinc, nickel, and iron. In muscle tissue of the fluorotic sheep, the copper levels were higher than those of the control group (p < 0.05). In the case of zinc, its levels were significantly higher in the controls than in the sheep with fluorosis (p < 0.01). No statistically significant differences were found in the muscle contents of nickel and zinc (p > 0.05). Compared to controls, the concentrations of zinc (0.01), iron (p < 0.05), and nickel (p < 0.05) were significantly higher in kidney tissues of fluorotic sheep, but there were no significant differences of the copper levels (p > 0.05). These results suggest that fluorosis significantly alters the mineral metabolism in muscle and kidney resulting in higher levels of mineral accumulation and excretion caused by fluoride intoxication. Further research shall focus on the enzymatic and metabolic activities of these and other trace elements.

Dietary copper and human health: Current evidence and unresolved issues

Although copper (Cu) is recognized as an essential trace element, uncertainties remain regarding Cu reference values for humans, as illustrated by discrepancies between recommendations issued by different national authorities. This review examines human studies published since 1990 on relationships between Cu intake, Cu balance, biomarkers of Cu status, and health. It points out several gaps and unresolved issues which make it difficult to assess Cu requirements. Results from balance studies suggest that daily intakes below 0.8 mg/day lead to net Cu losses, while net gains are consistently observed above 2.4 mg/day. However, because of an incomplete collection of losses in all studies, a precise estimation of Cu requirements cannot be derived from available data. Data regarding the relationship between Cu intake and potential biomarkers are either too preliminary or inconclusive because of low specificity or low sensitivity to change in dietary Cu over a wide range of intakes. Results from observation and intervention studies do not support a link between Cu and a risk of cardiovascular disease, cognitive decline, arthritis or cancer for intakes ranging from 0.6 to 3mg/day, and limited evidence exists for impaired immune function in healthy subjects with a very low (0.38 mg/day) Cu intake. However, data from observation studies should be regarded with caution because of uncertainties regarding Cu concentration in various foods and water. Further studies that accurately evaluate Cu exposure based on reliable biomarkers of Cu status are needed.

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.

Copper as ancillary diagnostic tool in preoperative evaluation of possible papillary thyroid carcinoma in patients with benign thyroid disease

Preoperative diagnosis of papillary thyroid carcinoma (PTC) comprises numerous diagnostic procedures which are mostly applicable in tertiary institutions. Normal thyroid function depends on the presence of many trace elements and copper (Cu) and zinc (Zn) are some of those. The study is based on retrospective review of 118 patients with preoperatively diagnosed benign thyroid disease (BTD) and 12 with PTC, who underwent thyroid surgery at the Center for Endocrine Surgery Clinical Center of Serbia, Belgrade, between 2010 and 2012. The objective was to evaluate concentrations of Cu and Zn in serum as possible prediction markers for PTC in patients who underwent surgery for preoperatively diagnosed BTD. Concentrations of Cu and Zn ions in serum were measured using atomic absorption spectrophotometer. Data were analyzed using methods of descriptive statistics, Anova and t-test (p < 0.05 was considered statistically significant). Definitive pathohistological findings revealed PTC in 23 (19.5%) and papillary microcarcinoma-mPTC in 13 (11.0%) of BTD patients. The concentrations of Cu ions in serum of PTC patients as well as in serum of patients with mPTC were significantly higher than in serum of BTD patients (p < 0.05). The concentrations of Zn ions and Cu/Zn ratio in serum of PTC and mPTC patients were not significantly higher than in serum of BTD patients. The concentration of Cu ions in serum of patients before thyroid surgery can be useful, easy available, and a low-cost tool in prediction of preoperatively undiagnosed PTC in patients with BTD.

Serum and tissue zinc in epithelial malignancies: a meta-analysis

BACKGROUND AND OBJECTIVES

Current studies give us inconsistent results regarding the association of neoplasms and zinc(II) serum and tissues concentrations. The results of to-date studies using meta-analysis are summarized in this paper.

METHODS

Web of Science (Science citation index expanded), PubMed (Medline), Embase and CENTRAL were searched. Articles were reviewed by two evaluators; quality was assessed by Newcastle-Ottawa scale; meta-analysis was performed including meta-regression and publication bias analysis.

RESULTS

Analysis was performed on 114 case control, cohort and cross-sectional studies of 22737 participants. Decreased serum zinc level was found in patients with lung (effect size = -1.04), head and neck (effect size = -1.43), breast (effect size = -0.93), liver (effect size = -2.29), stomach (effect size = -1.59), and prostate (effect size = -1.36) cancers; elevation was not proven in any tumor. More specific zinc patterns are evident at tissue level, showing increase in breast cancer tissue (effect size = 1.80) and decrease in prostatic (effect size = -3.90), liver (effect size = -8.26), lung (effect size = -3.12), and thyroid cancer (effect size = -2.84). The rest of the included tumors brought ambiguous results, both in serum and tissue zinc levels across the studies. The association between zinc level and stage or grade of tumor has not been revealed by meta-regression.

CONCLUSION

This study provides evidence on cancer-specific tissue zinc level alteration. Although serum zinc decrease was associated with most tumors mentioned herein, further--prospective--studies are needed.

Matrix metalloproteinase-9 and the Cu/Zn ratio as ancillary diagnostic tools in distinguishing between the classical and follicular variants of papillary thyroid carcinoma

The most common histological variants of papillary thyroid carcinoma (PTC), classical (CPTC) and follicular (FPTC), have different diagnostic features, molecular biology, and prognosis. Matrix metalloproteinase-9 (MMP-9) endopeptidase which degrades the components of the extracellular matrix is essential in the invasive growth and metastasizing of malignant tumors. The serum copper (Cu)/zinc (Zn) ratios are sensitive diagnostic and prognostic indicators in oncology since Cu- and Zn-dependent enzymes play important roles in the genesis and the progression of tumors. The aim of this study was to examine the expressions of MMP-9 in tissues of CPTC and FPTC, as well as to determine the Cu/Zn ratios in the same samples. MMP-9 was determined immunohistochemically, and the concentrations of copper and zinc in thyroid tissue were determined by means of flame atomic absorption spectrometry. The results obtained revealed significantly higher expressions of MMP-9 in CPTC in comparison with FPTC, as well as higher Cu/Zn ratios in CPTC than in FPTC. Thus, determining MMP-9 activities and the Cu/Zn ratios could improve the accuracy of the standard histopathological diagnosis of these two types of PTC.

Trace elements and heavy metals in hair of stage III breast cancer patients

This prospective study was designed to compare the hair levels of 36 elements in 52 patients with stage III breast cancer to those of an equal number of healthy individuals. Principal component and cluster analysis were used for source of identification and apportionment of heavy metals and trace elements in these two groups. A higher average level of iron was found in samples from patients while controls had higher levels of calcium. Both patients and controls had elevated levels of tin, magnesium, zinc, and sodium. Almost all element values in cancer patients showed higher dispersion and asymmetry than in healthy controls. Between the two groups, there were statistically significant differences in the concentrations of silver, arsenic, gold, boron, barium, beryllium, calcium, cadmium, cerium, cobalt, cesium, gadolinium, manganese, nickel, lead, antimony, scandium, selenium, and zinc (p < 0.05). Strong positive correlations were found between lead and gold (r = 0.785) in the cancer group and between palladium and cobalt (r = 0.945) in the healthy individuals. Our results show that there are distinct patterns of heavy metals and trace elements in the hair of breast cancer patients in comparison to healthy controls. These results could be of significance in the diagnosis of breast cancer.

Evaluation of Serum Zinc Level Under Malignant Condition and its Possible Implication on Improving Cell-Mediated Immunity During Cancer Progression

Background

Zinc is an essential trace element required for different biological functions in a living body. Evaluating its concentration and effect during malignancy is important not only to assess the disease activity but also to evaluate its role in some important biological activities like immunity.

Methods

The experiments were carried out in transplanted, chemically induced and spontaneous tumors in mice. The serum zinc concentration (SZC) was determined under malignant condition and following treatment of solid tumor with anti-cancer agents. The importance of evaluating Cu/Zn ratio (CZR) was also determined. To evaluate its role in immune response during malignancy, studies were carried out on induced tumor bearing animals.

Results

The results showed that SZC had an inverse correlation with the progression of the disease. It was significantly reduced in all forms of malignancy, more so in spontaneous and induced forms of the disease. Extensive studies done with the solid form of induced tumor, established the importance of estimating the concentration of Zn, in addition to that of copper, in assessing the disease activity following treatment with anti-cancer agents. With regression of the tumor mass, there was a significant elevation in the SZC and depression in the serum copper concentration (SCC) compared to their levels prior to treatment. This was also reflected on the value of copper zinc ratio (CZR); with the onset of tumor regression, a significant reduction in CZR was noted in the tumor bearing animals compared to their untreated levels. As the state of ‘regression’ in the tumor mass was maintained for a considerable period of time following treatment with anti-cancer agents along with elevated zinc levels, we considered the role of zinc in controlling the tumor growth, indirectly. We observed that zinc is able to stimulate lymphocyte proliferation that may directly impact on the immune response of tumor bearing host.

Conclusions

Zinc appears to play a role in tumor progression and regression and in stimulating lymphocyte proliferation. It is hypothesized that supplementing zinc to malignant subjects prior to and following therapeutic intervention with anti-cancer agents could help improve immune response of the host against existing tumor.

Study of selected trace elements in cancerous and non-cancerous human breast tissues from Sudanese subjects using instrumental neutron activation analysis

This study was performed to investigate the influence of cancer on selected trace elements among Sudanese patients with confirmed breast cancer. Instrumental neutron activation analysis was used to estimate contents of Se, Zn, Fe, Cr, Rb, Cs, Co and Sc in 40 subjects. Wilcoxon signed ranks test was used to examine if there was any difference in the concentrations of elements from normal and malignant tissues. It was found that Se, Zn and Cr elements from the malignant tissues are significantly elevated (P < 0.05) compared to the normal tissue. The results obtained have shown consistency with results obtained by some previous studies.

Levels of zinc, selenium, calcium, and iron in benign breast tissue and risk of subsequent breast cancer

Previous studies that have assessed breast cancer in relation to zinc, selenium, calcium, and iron have yielded inconsistent results but have not measured breast tissue levels. In a case-control study involving 252 matched pairs nested in a cohort of 9,315 women with benign breast disease, we investigated these associations by directly measuring elemental levels in breast tissue using X-ray fluorescence spectroscopy. Quintile analyses revealed positive associations of breast cancer, of borderline statistical significance, with zinc [highest versus lowest quintile: odds ratio (OR), 1.37; 95% confidence limit (95% CL), 0.91, 2.05; P(trend) = 0.04], iron (highest versus lowest quintile: OR, 1.58; 95% CL, 1.02, 2.44; P(trend) = 0.07), and calcium (highest versus lowest quintile: OR, 1.46; 95% CL, 0.98, 2.17; P(trend) = 0.14), but little association with selenium (highest versus lowest quintile: OR, 1.10; 95% CL, 0.72, 1.68; P(trend) = 0.76). The associations were weakened by mutual adjustment. Furthermore, after stratification by menopausal status, the positive association between iron and breast cancer was confined to postmenopausal women (highest versus lowest quintile: OR, 2.77; 95% CL, 1.25, 6.13; P(trend) = 0.008), whereas the associations for zinc, calcium, and selenium did not differ by menopausal stratum. In conclusion, our data raise the possibility that relatively high levels of zinc, iron, and calcium in benign breast tissue may be associated with a modest increase in risk of subsequent breast cancer.

Inhibition of extracellular signal regulated kinase (ERK) leads to apoptosis inducing factor (AIF) mediated apoptosis in epithelial breast cancer cells: the lack of effect of ERK in p53 mediated copper induced apoptosis

Recent studies have shown that MEK/ERK-mediated signals play a major role in regulation of activity of p53 tumor suppressor protein. In this study, we investigated whether or not there is functional interaction between p53 and MEK/ERK pathways in epithelial breast cancer cells exposed to copper or zinc. We demonstrated that expression of wild-type p53 induced by copper or zinc significantly reduced phosphorylation of extracellular signal regulated kinase (ERK) in epithelial breast cancer MCF7 cells. Mutation or suppression of p53 in MDA-MB231 and MCF7-E6 cells, respectively, resulted in a strong ERK phosphorylation in the presence of metals. Weak ERK phosphorylation in MCF7 cells induced by copper or zinc was linked to mitochondrial disruption and apoptosis. Furthermore, inhibition of ERK through addition of PD98059 stimulated p53 activation in MCF7 cells and also led to upregulation of p53 downstream targets, p21 and Bax, which is a proapototic member of Bcl-2 family triggering mitochondrial pore opening. Moreover, blockage of the MEK/ERK pathway caused a breakdown of the mitochondrial membrane potential accompanied by an elevation in the ROS production. Disruption of p53 expression attenuated the depolarization of the mitochondrial membrane and ROS generation. Furthermore, PD98059 initiated apoptosis inducing factor (AIF) translocation from mitochondria to the nucleus in MCF7 cells; which are depleted in caspase 3. Interestingly, repression of MEK/ERK pathway did not intensify the cell stress caused by metal toxicity. Therefore, these findings demonstrate that MEK/ERK pathway plays an important role in downregulation of p53 and cell survival. Inhibition of ERK can lead to apoptosis via nuclear relocation of AIF. However, metal-induced activation of p53 and mitochondrial depolarization appears to be independent of ERK. Our data suggest that copper induces apoptosis through depolarization of mitochondrial membrane with release of AIF, and this process is MEK/ERK independent.

["Do you have a remedy for macular degeneration?" A field study about the advice given on dietary supplementation in 60 German pharmacies]

PURPOSE

Since completion of the AREDS study, evidence has accumulated to suggest that some form of dietary supplementation may be of value in special individuals who are at risk of progressive age-related macular degeneration (ARMD). We wanted to find out which of the many supplements available are recommended in practice and which instructions, promises, and purchasing arguments are used by German pharmacies.

METHODS

A blinded consultation following a standardized protocol was carried out in 60 pharmacies.

RESULTS

In 36 pharmacies specific products for dietary supplementation were recommended, but the dosage never complied with the AREDS study, and in 24 pharmacies, the necessity for a medical examination or consultation with an ophthalmologist was not mentioned. Possible interactions with other drugs or side effects were generally excluded.

CONCLUSIONS

Potential risks of supplement intake were underestimated. Medical knowledge of the most frequent cause of blindness in the Western world was insufficient. A clear policy of recommendations according to evidence-based criteria is needed.

Raw and Cooked Vegetables, Fruits, Selected Micronutrients, and Breast Cancer Risk: A Case-Control Study in Germany

In 1998-2000, a case-control study of breast cancer was conducted in Heidelberg, Germany. Three hundred ten consecutively recruited cases with primary breast cancer were matched according to 10-yr age groups to 353 controls with conditions unrelated to diet or endocrine disorders. Intake of raw vegetables, total vegetables, and whole-grain products was inversely associated with breast cancer risk (highest vs. lowest quartile adjusted odds ratio [OR] 0.51, 95% confidence interval [CI] 0.31-0.84; OR = 0.62, 95% CI = 0.38-1.02; and OR = 0.57; 95% CI = 0.34-0.95, respectively). Also, high intake of some selected vitamins and minerals possessing putative DNA-stabilizing properties displayed significant inverse risk associations. Adjusted ORs were as follows: vitamin C (OR = 0.49, 95% CI = 0.2-0.88), folate equivalents (OR = 0.47, 95% CI = 0.25-0.88), b-carotene (OR = 0.46, 95% CI = 0.27-0.80), zinc (OR = 0.35, 95% CI = 0.15-0.78), and copper (OR = 0.51, 95% CI = 0.31-1.03). In contrast, no significant association with risk was seen for an increased intake of fruits, cooked vegetables, fiber, calcium, manganese, or iron. In this population of German women, components of raw vegetables and some micronutrients appear to decrease breast cancer risk.

Using wound fluid analyses to identify trace element requirements for efficient healing

A series of wound fluid and blood plasma samples from 20 patients with breast cancer were analysed by Potentiometric Stripping Analysis and computer-aided chemical speciation to quantify the concentrations of the trace elements of copper and zinc in the samples and to investigate the individual species of copper and zinc present. Comparisons were made between total concentrations of copper and zinc in wound fluid, pre-operative blood plasma levels and reference values. A wound fluid model constructed using JESS identified the main copper and zinc species present. It was also used to investigate the effects of a change in pH and changes in the total concentrations of certain components on their predominance. The clinical significance of the research is discussed, together with suggestions for a continuation in the research.

Association between oxidative stress and changes of trace elements in patients with breast cancer

OBJECTIVES

To investigate the association between oxidative stress and certain trace elements in the blood of breast cancer patients.

DESIGN AND METHODS

Malondialdehyde (MDA) was measured in serum of patients with breast cancer (n = 35) and controls (n = 35) by high performance liquid chromatography. Trace elements were determined by atomic absorption spectrophotometry.

RESULTS

In the present study, significantly increased lipid peroxidation, measured as MDA, was demonstrated in the serum of breast cancer patients (p < 0.01). The concentrations of zinc and iron remained unaltered. However, the mean serum copper level in patients with breast cancer was significantly higher than the control group (p < 0.01). In addition, the mean serum selenium level in patients with stage III was significantly lower than the control group (p < 0.05). Moreover, a positive correlation was also observed between copper and MDA levels in the patient group but not in the control group.

CONCLUSION

In the present study, the presence of an association between oxidative stress and trace elements was observed in patients with breast cancer. We suggest that increased oxidative stress in patients with breast cancer may result from changes in the levels of certain trace elements.

Trace element correlations in the blood of Indian women with breast cancer

Fourteen minor (Na, K, P, Fe) and trace (Br, Co, Cr, Cs, Hg, Rb, Sb, Se, Sr, Zn) elements have been determined in pre- and postoperative blood samples of 10 breast-cancer-affected. Indian women and compared with controls. The study showed elevation of Cr, Hg, Fe, Rb, Sb, and Zn and lowering of Se, K, P, and Sr contents in the blood of cancer patients. Most elemental contents in pre- and postoperative stages remain unaltered except Br, Co, and Sb. Statistical significance of Fe, Se, Zn, and Hg levels has been tested by box plots. Lowering of Se in blood (-54.4%) is correlated with its enhancement in cancerous breast tissue (94.7%) of various clinical stages. Se/Zn and Se/Fe ratios are lowered in the blood of cancer patients, whereas Na/K ratio is only marginally enhanced. An attempt has been made to correlate Se levels with the dietary intake and breast cancer risk vis-a-vis American and Japanese women.

Trace elements and superoxide dismutase in benign and malignant breast diseases

This study was planned to determine the probable changes in trace element levels and superoxide dismutase (SOD) activity in women with neoplastic breast diseases. Measurements were performed in three different groups. The first group consisted of 20 healthy women, control group, the second group contained 16 patients with benign breast disease and the third group contained 39 patients with malignant breast disease. The trace element concentrations were determined by using atomic absorption spectrophotometry and SOD activity by using spectrophotometry. When compared with the control values, the plasma copper levels were slightly increased in the second group and significantly in the third group (p < 0.001). The difference between the benign and malignant groups was also significant (p < 0.001). The red cell copper values showed a marked decrease in both groups (p < 0 001). Although there were increases in the plasma zinc levels of both patient groups, the differences were not significant statistically. But, the red cell zinc values showed an significant increase in benign and malignant patients compared to the control group (p < 0.001) (p < 0.001). The plasma magnesium and red cell magnesium values did not show significant differences. The red cell SOD activity showed an significant increase in the benign and malignant patient groups (p < 0.001). The results of this study suggested that reactive oxygen metabolites may play a pathogenetic role in the both benign and malignant tumor development, which is reflected by the change in SOD activity, and in trace element concentrations.

A case-control study on selenium, zinc, and copper in plasma and hair of subjects affected by breast and lung cancer

The purpose of our study was to investigate the relationship between plasma and hair levels of Se, Zn, and Cu, and cancer. We selected a total of 66 patients affected by either breast (38) or lung (28) cancer. They entered into the study at the onset of disease, and before any chemical or radiotherapy. Controls were randomly selected among healthy people and were matched for sex, age, smoking habits, and residence. In the group of breast cancer, a significant decrease in hair Se was found compared to controls (p < 0.01), whereas plasma Se was only slightly decreased. No difference between cases and controls was detected in both hair and plasma levels of Zn and Cu. Subjects who developed lung cancer were significantly lower in hair Zn (p < 0.05) and Cu (p < 0.01) than controls, whereas there was no difference with regard to Se. In addition, plasma Cu of these patients was increased as compared to controls.

Serum copper and zinc levels and copper/zinc ratio in patients with breast cancer

Serum copper, zinc levels, and the Cu/Zn ratio were evaluated in 31 patients with breast cancer and 35 healthy controls. Copper and zinc were determined by atomic absorbtion spectrophotometry. The mean serum copper level and the mean Cu/Zn ratio in patients with breast cancer were significantly higher than the control group (p < 0.001 and p < 0.001). In addition, the mean serum zinc level in patients with breast cancer was significantly lower than the control group (p < 0.001). Neither serum copper and zinc levels nor the Cu/Zn ratio were of value in discriminating of the disease activity and severity. Interestingly, the Cu/Zn ratio in premenopausal patients was higher than postmenopausal patients (p < 0.05) and this was not related to age. The further combined biological and epidemiological studies are necessary to investigate the roles of copper and zinc in breast cancer.

Quantitative analysis of copper, zinc and copper/zinc ratio in selected human brain tumors

Serum copper and zinc concentrations and copper/zinc ratios have been shown to be increased in several types of human malignancies, including human brain tumors. In this study, copper and zinc levels and copper/zinc ratios were determined by atomic absorption analysis in tissue and serum from 29 primary and metastatic brain tumor patients. Metastatic carcinomas and malignant gliomas revealed significantly higher tissue copper concentrations than control tissues and meningiomas. Malignant gliomas demonstrated significantly higher tissue copper/zinc ratios. Both serum copper and copper/zinc ratio were significantly higher in the metastatic carcinoma group than control; however, serum copper levels in malignant glioma patients were not significantly different from control tissues. There were no differences both in the serum and the tissue concentrations of these trace elements in meningiomas and controls. These data suggested that copper, an important angiogenic factors, is accumulated within the malignant tissues of metastatic carcinoma and malignant glioma, but not meningiomas. These findings may have implications regarding angiogenesis in these tumors.

The effect of postoperative radiotherapy on leukocyte zinc, serum trace elements and nutritional status of breast cancer patients

Mononuclear (MNC) and polymorphonuclear cell (PMNC) zinc content was determined together with serum zinc, copper, selenium and iron concentrations in 24 operable breast cancer patients during and after postoperative radiotherapy. Anthropometric and biochemical indices of nutritional status were measured as background data. The measurements were carried out in the years 1987-1988. Nine patients used unconventional multivitamin or trace element preparations. A steady but statistically insignificant decrease in PMNC zinc was seen during treatment. No changes occurred in MNC zinc. Serum copper levels increased in five patients possibly due to tamoxifen treatment, but no other alterations occurred in serum trace element levels. Appetite was well maintained and nutritional status remained unaltered. Postoperative radiotherapy for breast carcinoma had thus no effect on either trace element or nutritional status. Patient-initiated alternative treatments did not significantly affect their trace element levels. This was probably due to small supplementation doses or irregular use of the preparations.

The pattern of risk factors for breast cancer in a southern France population. Interest for a stratified analysis by age at diagnosis

A hospital-based case-control study was conducted over 4 years in Southern France to assess the pattern of established risk factors for breast cancer and to examine its variation according to age at diagnosis. Cases studied (450) were women admitted to the Montpellier Cancer Institute, with histologically confirmed primary breast carcinoma. Controls (576) were patients from a nearby hospital admitted in the early stages of a neurological or mild psychological diseases and from a clinic for general surgery. Any patient with malignant tumours, chronic and cardiovascular diseases were excluded. The total population globally showed the commonly reported pattern for these risk factors. When stratified by age, the reproductive factors occurring early in life (menarche, first full term pregnancy) were shown to be significant risk factors only in the youngest group of patients and do not seem to influence risk in older women, for whom risk factors are those occurring later in life (menopause, obesity). This suggests a complex involvement of the reproductive and sociodemographic features with the various stages of the 'natural history' of breast cancer.