Plasma ferritin levels, HFE polymorphisms, and risk of pancreatic cancer among Chinese Han population

Toxic Metal and Essential Element Concentrations in the Blood and Tissues of Pancreatic Ductal Adenocarcinoma Patients

BACKGROUND

Pancreatic ductal adenocarcinoma (PDAC) is a highly aggressive lethal neoplasm, and it has an average 5-year survival rate of less than 10%. Although the factors that influence PDAC development remain unclear, exposure to toxic metals or the imbalance in essential elements may have a role in PDAC-associated metabolic pathways.

METHODS

This study determined the concentrations of Cd, Cr, Cu, Fe, Mn, Ni, Pb, Se and Zn in whole blood, cancer and non-cancer tissues of patients affected by PDAC, and compared them with levels in healthy controls using inductively coupled plasma mass spectrometry.

RESULTS

Results of the whole blood showed significantly higher levels of Cr, Cu and Cu/Zn ratio in PDAC patients compared to the controls. In addition, the concentrations of Cu, Se, Fe and Zn significantly increased in cancer tissue compared to the healthy counterparts.

CONCLUSIONS

This study revealed evidence of altered metal levels in the blood and pancreatic tissues of PDAC patients with respect to healthy controls. These changes may contribute to multiple mechanisms involved in metal-induced carcinogenesis, including oxidative stress, DNA damage, genetic alteration, decreased antioxidant barriers and inflammatory responses. Thus, the analysis of metals can be used in the diagnosis and monitoring of PDAC neoplasms.

Hereditary Hemochromatosis Variant Associations with Incident Nonliver Malignancies: 11-Year Follow-up in UK Biobank

BACKGROUND

In European ancestry populations, iron overload disorder hereditary hemochromatosis is predominantly caused by HFE p.C282Y and p.H63D mutations. Male p.C282Y homozygotes have markedly increased hepatic malignancy incidence, but risks for other cancers in male and female homozygotes are unclear.

METHODS

451,143 UK Biobank European ancestry participants (aged 40-70 years; 54.3% female) were followed (mean 11.6 years) via hospital admissions and national cancer registries. We estimated risks of any incident cancer (other than nonmelanoma and liver cancer) and common incident cancers [bladder, blood (with subanalyses of leukemia and lymphoma), bone, brain, breast, colorectal, kidney, lung, melanoma, esophageal, ovarian, pancreatic, prostate and stomach] in those with p.C282Y and p.H63D genotypes, compared with participants without HFE mutations.

RESULTS

Male p.C282Y homozygotes (n = 2,890, 12.1% with baseline diagnosed hereditary hemochromatosis) had increased incidence of prostate cancer [6.8% vs. 5.4% without mutations; HR = 1.32; 95% confidence interval (CI), 1.07-1.63; P = 0.01; Bonferroni adjusted P = 0.17] during follow-up. In life table estimates from ages 40 to 75 years, 14.4% of male p.C282Y homozygotes are projected to develop prostate cancer (versus 10.7% without mutations, excess 3.8%; 95% CI, 1.3-6.8). No increases in risks were found for other studied cancers in male or female p.C282Y homozygotes, or in any other p.C282Y/p.H63D genotype groups of either sex.

CONCLUSIONS

In a large community sample of male p.C282Y homozygotes, there is suggestive evidence of increased prostate cancer incidence, with no evidence of excess of other studied (nonliver) cancers.

IMPACT

Replication of results in other large community genotyped cohorts are needed to confirm if clinical monitoring for prostate cancer is necessary in p.C282Y homozygous males.

Recent advances in the application of metallomics in diagnosis and prognosis of human cancer

Metals play a critical role in human health and diseases. In recent years, metallomics has been introduced and extensively applied to investigate the distribution, regulation, function, and crosstalk of metal(loid) ions in various physiological and pathological processes. Based on high-throughput multielemental analytical techniques and bioinformatics methods, it is possible to elucidate the correlation between the metabolism and homeostasis of diverse metals and complex diseases, in particular for cancer. This review aims to provide an overview of recent progress made in the application of metallomics in cancer research. We mainly focuses on the studies about metallomic profiling of different human biological samples for several major types of cancer, which reveal distinct and dynamic patterns of metal ion contents and the potential benefits of using such information in the detection and prognosis of these malignancies. Elevated levels of copper appear to be a significant risk factor for various cancers, and each type of cancer has a unique distribution of metals in biofluids, hair/nails, and tumor-affected tissues. Furthermore, associations between genetic variations in representative metalloprotein genes and cancer susceptibility have also been demonstrated. Overall, metallomics not only offers a better understanding of the relationship between metal dyshomeostasis and the development of cancer but also facilitates the discovery of new diagnostic and prognostic markers for cancer translational medicine.

Hemochromatosis, Iron Overload-Related Diseases, and Pancreatic Cancer Risk in the Surveillance, Epidemiology, and End Results (SEER)-Medicare

BACKGROUND

Experimental studies suggest that iron overload might increase pancreatic cancer risk. We evaluated whether prediagnostic hemochromatosis and iron-overload diseases, including sideroblastic and congenital dyserythropoietic anemias, and non-alcoholic-related chronic liver disease (NACLD) were associated with pancreatic cancer risk in older adults.

METHODS

We conducted a population-based, case-control study within the U.S. Surveillance, Epidemiology, and End Results Program (SEER)-Medicare linked data. Incident primary pancreatic cancer cases were adults > 66 years. Controls were alive at the time cases were diagnosed and matched to cases (4:1 ratio) by age, sex, and calendar year. Hemochromatosis, iron-overload anemias, and NACLD were reported 12 or more months before pancreatic cancer diagnosis or control selection using Medicare claims data. Adjusted unconditional logistic regression models were used to calculate ORs and 95% confidence intervals (CI) between hemochromatosis, sideroblastic and congenital dyserythropoietic anemias, NACLD, and pancreatic cancer.

RESULTS

Between 1992 and 2015, 80,074 pancreatic cancer cases and 320,296 controls were identified. Overall, we did not observe statistically significant associations between hemochromatosis, sideroblastic anemia, or congenital dyserythropoietic anemia and pancreatic cancer; however, sideroblastic anemia was associated with later primary pancreatic cancer (OR, 1.30; 95% CI, 1.03-1.64). NACLD was associated with first (OR, 1.10; 95% CI, 1.01-1.19), later (OR, 1.17; 95% CI, 1.02-1.35), and all (OR, 1.12; 95% CI, 1.04-1.20) pancreatic cancer.

CONCLUSIONS

Overall hemochromatosis and iron-overload anemias were not associated with pancreatic cancer, whereas NACLD was associated with increased risk in this large study of older adults.

IMPACT

These results partly support the hypothesis that iron-overload diseases increase pancreatic cancer risk.

Hepcidin-regulating iron metabolism genes and pancreatic ductal adenocarcinoma: a pathway analysis of genome-wide association studies

BACKGROUND

Epidemiological studies have suggested positive associations for iron and red meat intake with risk of pancreatic ductal adenocarcinoma (PDAC). Inherited pathogenic variants in genes involved in the hepcidin-regulating iron metabolism pathway are known to cause iron overload and hemochromatosis.

OBJECTIVES

The objective of this study was to determine whether common genetic variation in the hepcidin-regulating iron metabolism pathway is associated with PDAC.

METHODS

We conducted a pathway analysis of the hepcidin-regulating genes using single nucleotide polymorphism (SNP) summary statistics generated from 4 genome-wide association studies in 2 large consortium studies using the summary data-based adaptive rank truncated product method. Our population consisted of 9253 PDAC cases and 12,525 controls of European descent. Our analysis included 11 hepcidin-regulating genes [bone morphogenetic protein 2 (BMP2), bone morphogenetic protein 6 (BMP6), ferritin heavy chain 1 (FTH1), ferritin light chain (FTL), hepcidin (HAMP), homeostatic iron regulator (HFE), hemojuvelin (HJV), nuclear factor erythroid 2-related factor 2 (NRF2), ferroportin 1 (SLC40A1), transferrin receptor 1 (TFR1), and transferrin receptor 2 (TFR2)] and their surrounding genomic regions (±20 kb) for a total of 412 SNPs.

RESULTS

The hepcidin-regulating gene pathway was significantly associated with PDAC (P = 0.002), with the HJV, TFR2, TFR1, BMP6, and HAMP genes contributing the most to the association.

CONCLUSIONS

Our results support that genetic susceptibility related to the hepcidin-regulating gene pathway is associated with PDAC risk and suggest a potential role of iron metabolism in pancreatic carcinogenesis. Further studies are needed to evaluate effect modification by intake of iron-rich foods on this association.

Iron Metabolism in Cancer Progression

Iron is indispensable for cell metabolism of both normal and cancer cells. In the latter, several disruptions of its metabolism occur at the steps of tumor initiation, progression and metastasis. Noticeably, cancer cells require a large amount of iron, and exhibit a strong dependence on it for their proliferation. Numerous iron metabolism-related proteins and signaling pathways are altered by iron in malignancies, displaying the pivotal role of iron in cancer. Iron homeostasis is regulated at several levels, from absorption by enterocytes to recycling by macrophages and storage in hepatocytes. Mutations in HFE gene alter iron homeostasis leading to hereditary hemochromatosis and to an increased cancer risk because the accumulation of iron induces oxidative DNA damage and free radical activity. Additionally, the iron capability to modulate immune responses is pivotal in cancer progression. Macrophages show an iron release phenotype and potentially deliver iron to cancer cells, resulting in tumor promotion. Overall, alterations in iron metabolism are among the metabolic and immunological hallmarks of cancer, and further studies are required to dissect how perturbations of this element relate to tumor development and progression.

Tumor-initiating cells of breast and prostate origin show alterations in the expression of genes related to iron metabolism

The importance of iron in the growth and progression of tumors has been widely documented. In this report, we show that tumor-initiating cells (TICs), represented by spheres derived from the MCF7 cell line, exhibit higher intracellular labile iron pool, mitochondrial iron accumulation and are more susceptible to iron chelation. TICs also show activation of the IRP/IRE system, leading to higher iron uptake and decrease in iron storage, suggesting that level of properly assembled cytosolic iron-sulfur clusters (FeS) is reduced. This finding is confirmed by lower enzymatic activity of aconitase and FeS cluster biogenesis enzymes, as well as lower levels of reduced glutathione, implying reduced FeS clusters synthesis/utilization in TICs. Importantly, we have identified specific gene signature related to iron metabolism consisting of genes regulating iron uptake, mitochondrial FeS cluster biogenesis and hypoxic response (ABCB10, ACO1, CYBRD1, EPAS1, GLRX5, HEPH, HFE, IREB2, QSOX1 and TFRC). Principal component analysis based on this signature is able to distinguish TICs from cancer cells in vitro and also Leukemia-initiating cells (LICs) from non-LICs in the mouse model of acute promyelocytic leukemia (APL). Majority of the described changes were also recapitulated in an alternative model represented by MCF7 cells resistant to tamoxifen (TAMR) that exhibit features of TICs. Our findings point to the critical importance of redox balance and iron metabolism-related genes and proteins in the context of cancer and TICs that could be potentially used for cancer diagnostics or therapy.

Meta-Analysis of the Association between H63D and C282Y Polymorphisms in HFE and Cancer Risk

BACKGROUND

Previous studies suggested that the H63D and C282Y polymorphisms in the HFE genes were susceptible to many cancer types, nevertheless, the present results were inconclusive. Thus, the present study was aimed to evaluate the association between the HFE polymorphisms (H63D and C282Y) and cancer risk via meta-analysis.

MATERIALS AND METHODS

We retrieved PubMed, Google Scholar, Embase and Web of Science databases for all eligible studies up to April 1, 2015. All the statistical analysis was conducted by STATA 12.0.

RESULTS

Finally, a total of 20 publications including 24 case-control studies, comprising 6,524 cases and 31,080 controls for HFE-C282Y polymorphism and 19 publications including 21 case control studies, comprising 5,648 cases and 14,257 controls for HFE-H63D polymorphism were enrolled in our analysis. An increased risk for overall cancer risk was identified in HFE-H63D polymorphism under allele contrast (D vs H: OR=1.153; 95%CI=1.031- 1.289, Pheterogeneity=0.002), homozygotes vs wide type (DD vs HH: OR=1.449; 95%CI=1.182-1.777, Pheterogeneity=0.391), dominant model (DD+HD vs HH: OR=1.145; 95%CI=1.007-1.301, Pheterogeneity=0.002) and recessive model (DD vs HD+HH: OR=1.416 ; 95%CI=1.156-1.735, Pheterogeneity=0.549), as well as HFE- C282Y under homozygotes vs wide type (YY vs CC: OR=1.428, 95%CI=1.017-2.006, Pheterogeneity=0.220). In addition, in the stratified analysis by cancer type, an increased risk was identified in hepatocellular carcinoma and breast cancer in C282Y polymorphism, as well as pancreatic cancer in H63D polymorphism, whereas a decreased risk of colorectal cancer was identified in C282Y polymorphism.

CONCLUSIONS

Present study suggested that H63D and C282Y polymorphisms associated with an increased risk of overall cancer. Nevertheless, well- designed study with large sample size will be continued on this issue of interest.