Antioxidant Defense Capacity Is Reduced in Thyroid Stem/Precursor Cells Compared to Differentiated Thyrocytes.

There is much evidence linking oxidative stress to thyroid cancer, and stem cells are thought to play a key role in the tumor-initiating mechanism. Their vulnerability to oxidative stress is unexplored. This study aimed to comparatively evaluate the antioxidant capacity of stem/precursor thyroid cells and mature thyrocytes. Human stem/precursor cells and mature thyrocytes were exposed to increasing concentrations of menadione, an oxidative-stress-producing agent, and reactive oxygen species (ROS) production and cell viability were measured. The expression of antioxidant and detoxification genes was measured via qPCR as well as the total antioxidant capacity and the content of glutathione. Menadione elevated ROS generation in stem/precursor thyroid cells more than in mature thyrocytes. The ROS increase was inversely correlated (p = 0.005) with cell viability, an effect that was partially prevented by the antioxidant curcumin. Most thyroid antioxidant defense genes, notably those encoding for the glutathione-generating system and phase I detoxification enzymes, were significantly less expressed in stem/precursor thyroid cells. As a result, the glutathione level and the total antioxidant capacity in stem/precursor thyroid cells were significantly decreased. This reduced antioxidant defense may have clinical implications, making stem/precursor thyroid cells critical targets for environmental conditions that are not detrimental for differentiated thyrocytes.

Heavy Metals in the Environment and Thyroid Cancer.

In recent decades, the incidence of thyroid cancer has increased more than most other cancers, paralleling the generalized worldwide increase in metal pollution. This review provides an overview of the evidence supporting a possible causative link between the increase in heavy metals in the environment and thyroid cancer. The major novelty is that human thyroid stem/progenitor cells (thyrospheres) chronically exposed to different metals at slightly increased environmentally relevant concentrations show a biphasic increase in proliferation typical of hormesis. The molecular mechanisms include, for all metals investigated, the activation of the extracellular signal-regulated kinase (ERK1/2) pathway. A metal mixture, at the same concentration of individual metals, was more effective. Under the same conditions, mature thyrocytes were unaffected. Preliminary data with tungsten indicate that, after chronic exposure, additional abnormalities may occur and persist in thyrocytes derived from exposed thyrospheres, leading to a progeny population of transformation-prone thyroid cells. In a rat model predisposed to develop thyroid cancer, long-term exposure to low levels of metals accelerated and worsened histological signs of malignancy in the thyroid. These studies provide new insight on metal toxicity and carcinogenicity occurring in thyroid cells at a low stage of differentiation when chronically exposed to metal concentrations that are slightly increased, albeit still in the "normal" range.

Insulin Receptor Isoforms Differently Regulate Cell Proliferation and Apoptosis in the Ligand-Occupied and Unoccupied State.

The insulin receptor (IR) presents two isoforms (IR-A and IR-B) that differ for the α-subunit C-terminal. Both isoforms are expressed in all human cells albeit in different proportions, yet their functional properties-when bound or unbound to insulin-are not well characterized. From a cell model deprived of the Insulin-like Growth Factor 1 Receptor (IGF1-R) we therefore generated cells exhibiting no IR (R-shIR cells), or only human IR-A (R-shIR-A), or exclusively human IR-B (R-shIR-B) and we studied the specific effect of the two isoforms on cell proliferation and cell apoptosis. In the absence of insulin both IR-A and IR-B similarly inhibited proliferation but IR-B was 2-3 fold more effective than IR-A in reducing resistance to etoposide-induced DNA damage. In the presence of insulin, IR-A and IR-B promoted proliferation with the former significantly more effective than the latter at increasing insulin concentrations. Moreover, only insulin-bound IR-A, but not IR-B, protected cells from etoposide-induced cytotoxicity. In conclusion, IR isoforms have different effects on cell proliferation and survival. When unoccupied, IR-A, which is predominantly expressed in undifferentiated and neoplastic cells, is less effective than IR-B in protecting cells from DNA damage. In the presence of insulin, particularly when present at high levels, IR-A provides a selective growth advantage.

Thyroid Stem Cells But Not Differentiated Thyrocytes Are Sensitive to Slightly Increased Concentrations of Heavy Metals.

Thyroid cancer incidence is markedly increased in volcanic areas where residents are biocontaminated by chronic lifelong exposure to slightly increased metals in the environment. Metals can influence the biology of living cells by a variety of mechanisms, depending not only on the dose and length of exposure but also on the type and stage of differentiation of target cells. We explored the effect of five heavy metals (Cu, Hg, Pd, W and Zn) at nanomolar concentrations (the biocontamination level in residents of the volcanic area in Sicily where thyroid cancer is increased) on stimulating the proliferation of undifferentiated (thyrospheres) and differentiated human thyroid cells. Thyrosphere proliferation was significantly increased after exposure to each individual metal and a greater stimulating effect was observed when a mixture of the examined metals was used. No effect was seen in differentiated thyrocytes. For all metals, the dose-response curve followed a biphasic pattern that is typical of hormesis. Thyrosphere growth concerned the size rather than number, except with the metal mixture. An altered morphology was also observed in metal-treated thyrospheres. Metal-induced proliferation was due to activation of the ERK1/2 pathway, as confirmed by growth inhibition when ERK1/2 signaling was blocked. These studies show that stem/precursor thyroid cells are sensitive to small increases in environmental metal concentrations that are harmless for differentiated thyrocytes.

Increased Thyroid Cancer Incidence in Volcanic Areas: A Role of Increased Heavy Metals in the Environment?

Thyroid cancer incidence is significantly increased in volcanic areas, where relevant non-anthropogenic pollution with heavy metals is present in the environment. This review will discuss whether chronic lifelong exposure to slightly increased levels of metals can contribute to the increase in thyroid cancer in the residents of a volcanic area. The influence of metals on living cells depends on the physicochemical properties of the metals and their interaction with the target cell metallostasis network, which includes transporters, intracellular binding proteins, and metal-responsive elements. Very little is known about the carcinogenic potential of slightly increased metal levels on the thyroid, which might be more sensitive to mutagenic damage because of its unique biology related to iodine, which is a very reactive and strongly oxidizing agent. Different mechanisms could explain the specific carcinogenic effect of borderline/high environmental levels of metals on the thyroid, including (a) hormesis, the nonlinear response to chemicals causing important biological effects at low concentrations; (b) metal accumulation in the thyroid relative to other tissues; and (c) the specific effects of a mixture of different metals. Recent evidence related to all of these mechanisms is now available, and the data are compatible with a cause-effect relationship between increased metal levels in the environment and an increase in thyroid cancer incidence.

Concentration of Metals and Trace Elements in the Normal Human and Rat Thyroid: Comparison with Muscle and Adipose Tissue and Volcanic Versus Control Areas.

Background: The concentration of trace elements and metals in the thyroid is the result of exposure, uptake, retention, and clearance. The specificity and selectivity of thyroid capacity to concentrate these elements relative to other tissues are not known. To obtain this information, we measured the tissue concentration of 26 elements in the thyroid, muscle, and fat of euthyroid human subjects and also in normal rats. Methods: At programmed surgery, small (<1 g) tissue fragments were collected in 77 euthyroid subjects. Macroscopically normal thyroid tissue, sternothyroid muscle, and neck subcutaneous fat samples were excised, and thyroid tissue was confirmed to be morphologically normal through microscopy. Tissue specimens (thyroid, hindlimb muscle, and abdominal fat) were also obtained from normal rats. Measurements of trace elements were performed on tissues using inductively coupled plasma mass spectrometry (DRC-ICP-MS). Results: Only 19 of the 26 investigated elements were measurable as 7 elements were below the limit of detection. The ranking concentration in human thyroid tissue, not considering iodide, indicated that Zn, Br, Cu, Cr, Se, and Mn represented over 95% of the measured elements. A similar ranking was observed in the rat thyroid. A comparison with other tissues indicated that in addition to I, also Br, Mn, Se, and Sn were significantly more concentrated in the thyroid, and this was also the case for the recognized carcinogens As, Cd, and Hg. As and Hg, but not Cd (which was not detectable in any of the rat tissues), were also more concentrated in the rat thyroid. Since human thyroid specimens were also obtained from residents of a volcanic area, where environmental pollution may cause human biocontamination, we compared the trace element concentration in specimens from the volcanic area with controls. Many trace elements were slightly, but not significantly, increased in the volcanic area specimens. Conclusions: In the normal human thyroid, many trace elements, including Br, Mn, Se, and Sn, and the recognized carcinogens, As, Cd, and Hg, are significantly more concentrated than in muscle and fat of the same individual. Similar data were observed in rats. The reason for the differential element accumulation in the thyroid is unclear; a better understanding may be useful to further clarify thyroid biology.

Effect of low-dose tungsten on human thyroid stem/precursor cells and their progeny.

Thyroid cancer incidence is increased in volcanic areas where environment pollution biocontaminates residents. Tungsten (W) is the most increased heavy metal in drinking water of Mount Etna volcanic area where it exceeds the normal range in the urine of 27% inhabitants. The possible connection between increased tungsten and thyroid cancer has never been studied. We investigated in vitro the effect tungsten on both human thyrocytes in primary culture, thyrospheres (aggregates of stem/precursor thyroid cells) and thyrocytes differentiated from tungsten-exposed thyrospheres. Chronic exposure to low-dose (nanomolar range, as in the urines of volcanic area residents) soluble tungsten had major biological effects on thyroid stem/precursor cells, promoting growth with a biphasic (hormetic) dose-response and reducing apoptosis. No such effects were observed in mature thyrocytes. In addition, tungsten-exposed thyrospheres had abnormal expression of genes commonly altered also in thyroid cancer and increased activation of the DNA-repair proteins H2AX and 53BP1. Moreover, exposure to tungsten decreased thyrosphere differentiation, as indicated by the reduced expression of thyroid-specific genes in derived thyrocytes that also showed preneoplastic changes such as increased anchorage-independent growth, clonogenic growth and migration capacity. The mechanism of action of tungsten on thyroid stem/precursor cells is unclear but involves membrane G-proteins and activation of the ERK signaling pathway. These data indicate that chronic exposure to slightly increased tungsten, harmless for mature thyrocytes, importantly affects the biology of stem/precursor thyroid cells and of their progeny, inducing characteristics of preneoplastic transformation.

Short-term adverse effects of anticancer drugs in patients with type 2 diabetes.

The short-term adverse effects of anticancer drugs (AD) in patients with type 2 diabetes (T2D) are poorly studied and their management still represents an important challenge for clinicians. We carried out a retrospective single-center study in 168 patients with T2D and cancer, evaluating both the short-term effects of first-line AD on glycemic control and chronic diabetes complications. Average glycated hemoglobin significantly increased after AD compared to values before treatment (7.5 vs. 7.1%, p < 0.005). In 46.4% of patients, diabetes therapy had to be potentiated, in most cases (82.1%) by shifting to insulin. The use of alkylating agents and high-dose glucocorticoids predicted the need to potentiate diabetes therapy. After AD transaminase values significantly increased, whereas the estimated glomerular filtration rate decreased (in 12.5% <60 mL/min). Kinase inhibitors significantly increased the risk of microalbuminuria onset or progression. The present study provides a real-life information on the effects of different AD on the management of patients with T2D affected by several types of cancer.

Time to Separate Persistent From Recurrent Differentiated Thyroid Cancer: Different Conditions With Different Outcomes.

Context: Differentiated thyroid cancer (DTC) has an excellent prognosis, but up to 20% of patients with DTC have disease events after initial treatment, indistinctly defined as persistent/recurrent disease. Objective: To evaluate the prevalence and outcome of "recurrent" disease (relapse after being 12 months disease-free) compared with "persistent" disease (present ab initio since diagnosis). Design: Retrospective analysis of persistent/recurrent disease in patients with DTC (1990 to 2016) with 6.5 years of mean follow-up. Setting: Tertiary referral center for thyroid cancer. Patients: In total, 4292 patients all underwent surgery ± 131I treatment of DTC. Main Outcome Measures: DTC cure of disease persistence or recurrence. Results: A total of 639 of 4292 (14.9%) patients had disease events after initial treatment, most (498/639, 78%) with persistent disease and 141 (22%) with recurrent disease. Relative to patients with recurrent disease, patients with persistent disease were significantly older (mean age 46.9 vs 45.7 years) and with a lower female to male ratio (1.9/1 vs 4.8/1). Moreover, in this group, structured disease was more frequent (65.7% vs 41.1%), and more important, distant metastases were significantly more frequent (38.4% vs 17.0%). At multivariate analysis, male sex (OR = 1.7), age (OR = 1.02), follicular histotype (OR = 1.5), T status (T3; OR = 3), and N status (N1b; OR = 7.7) were independently associated with persistent disease. Only the N status was associated with recurrent disease (N1b; OR = 2.5). Conclusions: In patients with DTC not cured after initial treatment, persistent disease is more common and has a worse outcome than recurrent disease. Postoperative status evaluated during first-year follow-up may have important clinical implications for planning tailored treatment strategies and long-term follow-up procedures.

Differentiated thyroid cancer in children: Heterogeneity of predictive risk factors.

OBJECTIVE: To correlate clinical and pathological characteristics at diagnosis with patient long-term outcomes and to evaluate ongoing risk stratifications in a large series of paediatric differentiated thyroid cancers (DTC). STUDY DESIGN: Retrospective analysis of clinical and pathological prognostic factors of 124 paediatric patients with DTC (age at diagnosis <19 years) followed up for 10.4 ± 8.4 years. Patients with a follow-up >3 years (n = 104) were re-classified 18 months after surgery on the basis of their response to therapy (ongoing risk stratification). RESULTS: Most patients had a papillary histotype (96.0%), were older than 15 years (75.0%) and were diagnosed because of clinical local symptoms (63.7%). Persistent/recurrent disease was present in 31.5% of cases during follow-up, but at the last evaluation, only 12.9% had biochemical or structural disease. The presence of metastases in the lymph nodes of the lateral compartment (OR 3.2, 95% CI, 1.28-7.16, P = 0.01) was the only independent factor associated with recurrent/persistent disease during follow-up. At the last evaluation, biochemical/structural disease was associated with node metastases (N1a, N1b) by univariate but not multivariate analysis. Ongoing risk stratification compared to the initial risk classification method better identified patients with a lower probability of persistent/recurrent disease (NPV = 100%). CONCLUSIONS: In spite of the aggressive presentations at diagnosis, paediatric patients with DTC show an excellent response to treatment and often a favourable outcome. N1b status should be considered a strong predictor of persistent/recurrent disease which, as in adults, is better predicted by ongoing risk stratification.

Adverse glycaemic effects of cancer therapy: indications for a rational approach to cancer patients with diabetes.

Diabetes and cancer are common, chronic, and potentially fatal diseases that frequently co-exist. Observational studies have reported an increased risk of cancer in patients with diabetes. Furthermore, many patients with cancer already have diabetes, or develop hyperglycaemia as a consequence of the tumor or of cancer therapies, and coexisting diabetes confers a greater risk of mortality for many malignancies. Managing oncologic patients with diabetes is often complicated, since the co-existence of diabetes and cancer poses several complex clinical questions: what level of glycaemic control to achieve, which therapy to use, how to deal with glucocorticoid therapies and artificial nutrition, how diabetes complications can affect cancer management, which drug-drug interactions should be taken into account, or even how to manage diabetes at the end of life. In the clinical setting, both at hospital and at home, there are little agreed, evidence-based guidelines on the best management and criteria upon which clinical decisions should be based. A practical solution lies in the implementation of care networks based on communication and ongoing collaboration between Oncologists, Endocrinologists, and the nursing staff, with the patient at the centre of the care process. This manuscript aims to review the current evidence on the effect of cancer therapies on glucose metabolism and to address some of the more common challenges of diabetes treatment in patients with cancer.

Anaplastic Thyroid Cancer in Sicily: The Role of Environmental Characteristics.

BACKGROUND: Anaplastic thyroid cancer (ATC) is a rare but extremely aggressive cancer of the thyroid, contributing up to 30-40% of thyroid cancer-specific mortality. We analyzed ATC characteristics and survival rates in Sicily to evaluate the possible influence of environmental factors. With this aim, data regarding ATC incidences in urban/rural and industrial, iodine-deficient, and volcanic vs control areas were compared in Sicily as well as ATC data from Sicily and USA. METHODS: Using the Sicilian Register of Thyroid Cancer (SRTC) database incidence, age, gender, tumor size and histotype, extrathyroidal extension, stage, and coexistence with pre-existing differentiated thyroid cancer (DTC) were evaluated in different areas of Sicily and also compared with Surveillance Epidemiology and End Results data in USA. RESULTS: Forty-three ATCs were identified in Sicily in the period 2002-2009. In our series only age <70 years at diagnosis (p = 0.01), coexistence with DTC (p = 0.027) and tumor size ≤6 cm (p = 0.012) were significant factors for increased survival at univariate analysis (only age at multivariate analysis). No difference in ATC incidence was found in urban vs rural areas and in iodine-deficient and industrial vs control areas. By contrast, in the volcanic area of Sicily, where DTC incidence is doubled relative to the rest of the island, also ATC incidence was increased. ATC data in Sicily were similar to those reported in the same period in the USA where overall survival rate at 6 and 12 months, however, was smaller. CONCLUSION: The similar ATC data observed in Sicily and USA (having different genetic background and lifestyle) and the increased ATC incidence in the volcanic area of Sicily paralleling the increased incidence of papillary thyroid cancer are compatible with the possibility that casual additional mutations, more frequent in a background of increased cell replication like DCT, are the major causes of ATC rather than genetic background and/or direct environmental influences.

Insulin Receptor Isoforms in Physiology and Disease: An Updated View.

The insulin receptor (IR) gene undergoes differential splicing that generates two IR isoforms, IR-A and IR-B. The physiological roles of IR isoforms are incompletely understood and appear to be determined by their different binding affinities for insulin-like growth factors (IGFs), particularly for IGF-2. Predominant roles of IR-A in prenatal growth and development and of IR-B in metabolic regulation are well established. However, emerging evidence indicates that the differential expression of IR isoforms may also help explain the diversification of insulin and IGF signaling and actions in various organs and tissues by involving not only different ligand-binding affinities but also different membrane partitioning and trafficking and possibly different abilities to interact with a variety of molecular partners. Of note, dysregulation of the IR-A/IR-B ratio is associated with insulin resistance, aging, and increased proliferative activity of normal and neoplastic tissues and appears to sustain detrimental effects. This review discusses novel information that has generated remarkable progress in our understanding of the physiology of IR isoforms and their role in disease. We also focus on novel IR ligands and modulators that should now be considered as an important strategy for better and safer treatment of diabetes and cancer and possibly other IR-related diseases.

Intake of Boron, Cadmium, and Molybdenum enhances rat thyroid cell transformation.

BACKGROUND: Epidemiologic data in volcanic areas suggest that environmental factors might be involved in the increase of thyroid cancer (TC) incidence. Recent reports indicate that several heavy metals and metalloids are increased in volcanic areas. This study aims to evaluate the combined effect of three of these elements Boron (B), Cadmium (Cd), and Molybdenum (Mo) - all increased in the volcanic area of Mt. Etna, in Italy - on thyroid tumorigenesis in the rat. METHODS: Female Wistar rats prone to develop thyroid tumors by low-iodine diet and methimazole treatment received ad libitum drinking water supplemented with B, Cd, and Mo at concentrations in the range found in the urine samples of residents of the volcanic area. At 5 and 10 months animals were euthanized, and their thyroid analysed. Statistical analysis was performed with a 2-way unpaired t-test. RESULTS: No toxic effect of the three elements on the growth of the animals was observed. A significant increase of histological features of transformation was observed in thyroid follicular cells of rats treated with B, Cd, and Mo compared with those of control group. These abnormalities were associated with decreased iodine content in the thyroid. CONCLUSIONS: This study provides the evidence that slightly increased environmental concentrations of B, Cd, and Mo can accelerate the appearance of transformation marks in the thyroid gland of hypothyroid rats.

Thyroid Cancer in the Pediatric Age in Sicily: Influence of the Volcanic Environment.

BACKGROUND/AIM: Pediatric thyroid cancer (TC) is rare but its incidence is increasing. We analyzed incidence and characteristics of pediatric TC in Sicily and comparatively evaluated data from the volcanic and non-volcanic areas. MATERIALS AND METHODS: All incident pediatric (0-19 years) TCs in Sicily between 2002-2009 were analyzed for the area of residence and compared to data for adults. RESULTS: A total of 54 differentiated TCs (DTC) and nine medullary TCs were diagnosed in Sicily in children between 2002-2009. DTC age standardized rate for the world population (ASRw) was 0.8/105 in females and 0.2/105 in males, with a higher incidence in the volcanic area (ASRw=1.4/105 in females, 0.5/105 in males) vs. the rest of Sicily (ASRw=0.6/105 in females, 0.1/105 in males). Pediatric TCs were larger in size and more frequently with extrathyroid extension and lymph-node involvement in comparison to TCs in adults. CONCLUSION: In the volcanic environment of Sicily, TC incidence is markedly increased in children, suggesting a short-term effect of unidentified carcinogens of volcanic origin.

Prognostic Factors for Adrenocortical Carcinoma Outcomes.

PURPOSE: Adrenocortical carcinoma (ACC) is an aggressive tumor characterized by a high recurrence rate and poor response to treatment. This study analyzes a consecutive series of ACC patients to evaluate the prognostic value of various clinical and pathological characteristics. METHODS: We retrospectively evaluated 32 ACC patients followed at our Medical Center from 1997 to 2015 and evaluated the prognostic value of age at diagnosis, gender, tumor functional status, stage, and type of treatment with respect to overall survival (OS) and disease-free survival (DFS), as determined by Kaplan-Meier curves. RESULTS: ACC was associated with hormonal overproduction in 50% of cases, and patients with isolated hyperandrogenism had a better prognosis. Recurrence was observed in 12/26 (46.2%) patients with no evidence of disease after surgery. Tumor size [hazard ratio (HR) 1.32, 95% confidential intervals (CI) 1.12-1.64; p = 0.007], ki-67 (HR 1.06, 95% CI 1.02-1.11; p = 0.009) and advanced stage at diagnosis (III-IV) (HR 6.51, 95% CI 1.65-24.68; p = 0.006) were associated with recurrence in the 26 R0 patients in the univariate analysis. Advanced stage was an independent risk factor for recurrence in the multivariate analysis (HR 8.10, 95% CI 1.55-41.35; p = 0.01). Five-year survival was 40.0%. Positive resection margins (HR 10.61, 95% CI 3.02-38.31; p = < 0.001), ki-67 (HR 1.04, 95% CI 1.01-1.07; p = 0.01) and advanced stage (HR 11.31, 95% CI 1.45-87.76; p = 0.02) were associated with poor survival in all 32 patients, but only positive resection margins were an independent predictor of mortality in the multivariate analysis (HR 6.22, 95% CI 1.44-26.05; p = 0.01). CONCLUSION: ACC has a poor prognosis with a high recurrence rate. Tumor stage at diagnosis and the completeness of surgical excision are the most relevant prognostic factors.

Outcome of the Diffuse Sclerosing Variant of Papillary Thyroid Cancer: A Meta-Analysis.

INTRODUCTION: The diffuse sclerosing variant (DSV) of papillary thyroid cancer (PTC) is considered an aggressive histotype associated with poor prognosis. However, the available data for both the outcome and best management of this disease are inconsistent. METHODS: This study reviewed the current literature by searching PubMed up to November 30, 2015, using the search terms "diffuse sclerosing variant" and "papillary thyroid cancer (or carcinoma)" and selecting only studies evaluating recurrent/persistent disease and cancer-related mortality in both DSV and classic PTC (cPTC). The association with some features of aggressiveness at diagnosis, the risk of recurrence or persistence, and the risk of cancer-related death were reported as odds ratio (OR) with confidence intervals (CI). Meta-regression analysis was used to assess the effect of covariates across the studies. RESULTS: Ten studies met the eligibility criteria and contributed 585 DSV and 64,611 cPTC patients. Relative to patients with cPTC, patients with DSV exhibited a higher risk of extrathyroidal extension and lymph node and distant metastases. The risk of persistent/recurrent disease was three times higher in patients with DSV than it was in cPTC patients (OR = 3.19 [CI 1.86-5.49]). This risk was not different when only studies where post-surgical (131)I was routinely administered were considered (OR = 2.07 [CI 0.88-4.90]). The risk of cancer-related mortality was not different between DSV and cPTC (OR = 1.34 [CI 0.76-2.38]). CONCLUSIONS: This meta-analysis confirms the aggressive biological behavior of DSV thyroid cancer. When preoperatively suspected, total thyroidectomy with lymph node excision followed by radioiodine therapy should be the correct management for DSV.

Increased thyroid cancer incidence in a basaltic volcanic area is associated with non-anthropogenic pollution and biocontamination.

The increased thyroid cancer incidence in volcanic areas suggests an environmental effect of volcanic-originated carcinogens. To address this problem, we evaluated environmental pollution and biocontamination in a volcanic area of Sicily with increased thyroid cancer incidence. Thyroid cancer epidemiology was obtained from the Sicilian Regional Registry for Thyroid Cancer. Twenty-seven trace elements were measured by quadrupole mass spectrometry in the drinking water and lichens (to characterize environmental pollution) and in the urine of residents (to identify biocontamination) in the Mt. Etna volcanic area and in adjacent control areas. Thyroid cancer incidence was 18.5 and 9.6/10(5) inhabitants in the volcanic and the control areas, respectively. The increase was exclusively due to the papillary histotype. Compared with control areas, in the volcanic area many trace elements were increased in both drinking water and lichens, indicating both water and atmospheric pollution. Differences were greater for water. Additionally, in the urine of the residents of the volcanic area, the average levels of many trace elements were significantly increased, with values higher two-fold or more than in residents of the control area: cadmium (×2.1), mercury (×2.6), manganese (×3.0), palladium (×9.0), thallium (×2.0), uranium (×2.0), vanadium (×8.0), and tungsten (×2.4). Urine concentrations were significantly correlated with values in water but not in lichens. Our findings reveal a complex non-anthropogenic biocontamination with many trace elements in residents of an active volcanic area where thyroid cancer incidence is increased. The possible carcinogenic effect of these chemicals on the thyroid and other tissues cannot be excluded and should be investigated.