TPO genetic variants and risk of differentiated thyroid carcinoma in two European populations.

Thyroid cancer risk involves the interaction of genetic and environmental factors. The thyroperoxidase (TPO) has a key role in the iodine metabolism, being essential for the thyroid function. Mutations in the TPO gene are common in congenital hypothyroidism, and there are also signs of the implication of TPO in thyroid cancer. We performed a case-control association study of genetic variants in TPO and differentiated thyroid carcinoma (DTC) in 1,586 DTC patients and 1,769 controls including two European populations (Italy: 1,190 DTC and 1,290 controls; Spain: 396 DTC and 479 controls). Multivariate logistic regression analyses were performed separately for each population and each single-nucleotide polymorphism (SNP). From the three studied polymorphisms, significant associations were detected between DTC and rs2048722 and rs732609 in both populations (p < 0.05). In the Italian population, both SNPs showed a negative association (rs2048722, odds ratio [OR] = 0.79, 95% confidence interval [CI] = 0.63-1.00, p = 0.045; rs732609, OR = 0.72, 95% CI = 0.55-0.94, p = 0.016), whereas in the Spanish population, these SNPs showed a positive association (rs2048722, OR = 1.39, 95% CI = 1.03-1.89, p = 0.033; rs732609, OR = 1.41, 95% CI = 1.06-1.87, p = 0.018). The corresponding associations for papillary or follicular thyroid cancer were similar to those for all DTC, within population. No association was detected for the third TPO polymorphism in the Italian and the Spanish populations. Our results, for the first time, point to TPO as a gene involved in the risk of DTC, and suggest the importance of interactions between TPO variants and other unidentified population-specific factors in determining thyroid cancer risk.

Risk profiles and penetrance estimations in multiple endocrine neoplasia type 2A caused by germline RET mutations located in exon 10.

Multiple endocrine neoplasia type 2 is characterized by germline mutations in RET. For exon 10, comprehensive molecular and corresponding phenotypic data are scarce. The International RET Exon 10 Consortium, comprising 27 centers from 15 countries, analyzed patients with RET exon 10 mutations for clinical-risk profiles. Presentation, age-dependent penetrance, and stage at presentation of medullary thyroid carcinoma (MTC), pheochromocytoma, and hyperparathyroidism were studied. A total of 340 subjects from 103 families, age 4-86, were registered. There were 21 distinct single nucleotide germline mutations located in codons 609 (45 subjects), 611 (50), 618 (94), and 620 (151). MTC was present in 263 registrants, pheochromocytoma in 54, and hyperparathyroidism in 8 subjects. Of the patients with MTC, 53% were detected when asymptomatic, and among those with pheochromocytoma, 54%. Penetrance for MTC was 4% by age 10, 25% by 25, and 80% by 50. Codon-associated penetrance by age 50 ranged from 60% (codon 611) to 86% (620). More advanced stage and increasing risk of metastases correlated with mutation in codon position (609→620) near the juxtamembrane domain. Our data provide rigorous bases for timing of premorbid diagnosis and personalized treatment/prophylactic procedure decisions depending on specific RET exon 10 codons affected.

A novel germline variant in RET gene resulting in an additional cysteine in a family with familial medullary thyroid carcinoma.

Multiple endocrine neoplasia type 2 (MEN 2) is an autosomal dominant inherited disease, characterized by germ-line variants in RET proto-oncogene. Variants are frequently located in the RET extracellular cysteine-rich region domain, mainly affecting cysteines which are replaced by an alternative amino acid, resulting in a mispaired cysteine and the generation of RET dimers. We describe a novel c.1765A > T variant of RET proto-oncogene in a family with medullary thyroid carcinoma (MTC) that predicts the creation of an additional cysteine p.(Ser589Cys) in the cysteine-rich domain. In this site only three other punctual variants have been described, giving rise to extra cysteines. We have characterized the clinical phenotype of this family. The index case was a 79-year-old woman with MTC in both thyroid lobes. This variant co-segregates in this family in four affected members. One member was operated on at 31 years of age and already presented MTC, indicating that prophylactic thyroidectomy was appropriated. Variants predicting additional cysteines are not frequent in RET, and when present, they allow us to understand their implication in the disease. According to clinical data obtained in this family, this variant could be categorized as a moderate-risk of the disease.

Age-related neoplastic risk profiles and penetrance estimations in multiple endocrine neoplasia type 2A caused by germ line RET Cys634Trp (TGC>TGG) mutation.

RET testing in multiple endocrine neoplasia type 2 for molecular diagnosis is the paradigm for the practice of clinical cancer genetics. However, precise data for distinct mutation-based risk profiles are not available. Here, we survey the clinical profile for one specific genotype as a model, TGC to TGG in codon 634 (C634W). By international efforts, we ascertained all available carriers of the RET C634W mutation. Age at diagnosis, penetrance, and clinical complications were analyzed for medullary thyroid carcinoma (MTC), pheochromocytoma, and hyperparathyroidism (HPT), as well as overall survival. Our series comprises 92 carriers from 20 unrelated families worldwide. Sixty-eight subjects had MTC diagnosed at age 3-72 years (mean 29). Lymph node metastases were observed in 16 subjects aged 20-72 and distant metastases in 4 subjects aged 28-69. Forty-one subjects had pheochromocytoma detected at age 18-67 (mean 36). Amongst the 28 subjects with MTC and pheochromocytoma, six developed pheochromocytoma before MTC. Six subjects had HPT diagnosed at age 26-52 (mean 39). Eighteen subjects died; of the 16 with known causes of death, 8 died of pheochromocytoma and 4 of MTC. Penetrance for MTC is 52% by age 30 and 83% by age 50, for pheochromocytoma penetrance is 20% by age 30 and 67% by age 50, and for HPT penetrance is 3% by age 30 and 21% by age 50. These data provide, for the first time, RET C634W-specific neoplastic risk and age-related penetrance profiles. The data may facilitate risk assessment and genetic counseling.

Alpha defensins 1, 2, and 3: potential roles in dyslipidemia and vascular dysfunction in humans.

OBJECTIVES: Alpha-defensins are natural antibiotics made by neutrophils that have been reported to modulate cholesterol metabolism and vascular function; however, their role in vivo remains largely unknown. We hypothesized that alpha-defensins 1 to 3 (DEFA1-3) are associated with serum lipids and vascular reactivity in humans. METHODS AND RESULTS: One hundred thirteen apparently-healthy White men, participants in a prospective study of cardiovascular risk factors, were assessed for a lipid profile, insulin sensitivity (S(I), frequently-sampled intravenous glucose tolerance test), and non-stressed circulating DEFA1-3 (ELISA). In a subset of 52 subjects, vascular reactivity (high-resolution ultrasound of the brachial artery) was also assessed. Subjects in the highest quartile for plasma DEFA1-3 were found to be leaner and more insulin sensitive, and to have significantly reduced total and LDL-cholesterol, compared with subjects in the lowest quartile for circulating DEFA1-3 (P<0.0001 to P=0.002 for linear trend ANOVA). The associations with serum lipids persisted after adjustment for age, body mass index, insulin sensitivity, and smoking (which was associated with reduced plasma DEFA1-3 concentrations). Finally, endothelium-independent vasodilation increased with increasing circulating DEFA1-3 (P=0.003) and this association was not explained by age, body mass index, serum cholesterol, insulin sensitivity, or smoking. CONCLUSIONS: Circulating DEFA1-3 are associated with serum cholesterol and vascular reactivity in humans. Alpha-defensins may have clinical implications in patients with either hypercholesterolemia or vascular dysfunction.

Natural antibiotics and insulin sensitivity: the role of bactericidal/permeability-increasing protein.

The innate immune system can immediately respond to microorganism intrusion by helping to prevent further invasion. Bactericidal/permeability-increasing protein (BPI) is a major constituent of neutrophils that possesses anti-inflammatory properties. Inflammation is increasingly recognized as a component of the metabolic syndrome. We hypothesized that the production of BPI could be linked to insulin sensitivity and glucose tolerance. We studied circulating BPI across categories of glucose tolerance. We also studied whether these cross-sectional associations were of functional importance. For this reason, we investigated circulating bioactive lipopolysaccharide and the effects of changing insulin action-after treatment with an insulin sensitizer (metformin)-on circulating BPI in subjects with glucose intolerance. Finally, we tested whether a 3'-untranslated region (UTR) BPI polymorphism led to differences in BPI and insulin action among nondiabetic subjects. Age- and BMI-adjusted circulating BPI was significantly lower among patients with type 2 diabetes. Circulating BPI correlated negatively with fasting and postload glucose and insulin concentrations. In subjects with glucose intolerance, BPI was also linked to BMI, waist-to-hip ratio, and age- and BMI-adjusted insulin sensitivity. Bioactive lipopolysaccharide was negatively correlated with circulating BPI (r = -0.57, P < 0.0001) and positively with plasma lipopolysaccharide-binding protein (r = 0.54, P = 0.002). In parallel to improved insulin sensitivity, plasma BPI significantly increased in the metformin group but not in the placebo group. A 3'-UTR BPI polymorphism was simultaneously associated with plasma BPI concentration, waist-to-hip ratio, fasting and postload insulin concentration, fasting plasma triglycerides, and insulin sensitivity. These findings suggest that this component of the innate immune system is associated with metabolic pathways.

Differential regulation of insulin action and tumor necrosis factor alpha system activity by metformin.

BACKGROUND: Tumor necrosis factor alpha has a key role in insulin resistance. We study the effects of metformin on glucose tolerance, insulin resistance, beta cell function, and soluble tumor necrosis factor receptor (sTNFR) levels. METHODS: We performed a double-blind, randomized metformin-placebo study. Twenty-three subjects with impaired glucose tolerance or impaired fasting glucose were studied. Oral glucose tolerance, homeostasis model assessment, and continuous infusion of glucose with model assessment tests were used to evaluate glucose tolerance, insulin sensitivity, and beta cell function, respectively. Soluble tumor necrosis factor receptor levels were measured before and after therapy. Repeated measures analysis of variance was used for statistical analysis. RESULTS: After 12-week treatment, fasting glucose (110.1 +/- 9.9 to 98.9 +/- 15.7 mg/dl, P < .001), fasting insulin (11.6 +/- 5.4 to 8.8 +/- 3.5 mU/L, P = .05), fasting C-peptide (2.5 +/- 0.7 to 1.8 +/- 0.5 ng/mL, P < .05), and achieved C-peptide (5.2 +/- 1.2 to 4.2 +/- 1 ng/mL, P < .05) levels decreased in the metformin group. In addition, there was an improvement in insulin sensitivity (37.4% +/- 15.2% to 50.4% +/- 23.2%, P < .05) with unchanged sTNFR1 (2.0 +/- 0.8 to 2.3 +/- 1.2 microg/L, P = NS) and sTNFR2 (4.8 +/- 1.7 to 4.4 +/- 1.2 microg/L, P = NS) levels. CONCLUSIONS: Metformin is able to reverse insulin resistance and hyperglycemia in high-risk subjects for type 2 diabetes mellitus independently of the effects on tumor necrosis factor alpha system activity.

[Factors influencing incipient diabetic nephropathy: ESODIAH study]. / Factores que influyen en la aparición de la nefropatía diabética incipiente: estudio ESODIAH.

BACKGROUND AND OBJECTIVE: High cholesterol levels might contribute to the presence of albuminuria. The objective of our study was to evaluate the influence of lipid levels on the development of incipient diabetic nephropathy. Secondary objectives were to evaluate the effects of diabetes control, high blood pressure, age, sex, years of diabetes evolution, body mass index and smoking. PATIENTS AND METHOD: 930 subjects were enrolled in an open observational prospective cohort study of subjects with type 2 diabetes mellitus and high cholesterol levels (ESODIAH study) for 2 years. In our nephropathy study we selected 590 patients who had albuminuria measurements done. In every 4-month interval visit we made a clinical evaluation and blood analysis including HbA1c, lipid profile and microalbuminuria. Statistical analysis included t-Student, chi2 test, and binary logistic regressions. RESULTS: 51.7% men, aged 62.08 years of age and with an evolution of their diabetes of 8.49 years were studied. 40.6% had microalbuminuria and 59.4% had normoalbuminuria. High HbA1c correlated with the presence of albuminuria (odds ratio [OR] = 1.3; 95% confidence interval [CI], 1.12-1.55; p = 0.001). The development of microalbuminuria was more frequent in younger (OR = 0.93; 95% CI, 0.89-0.98), smoker (OR = 3.19; 95% CI, 1.02-9.96), subjects with high systolic blood pressure (OR = 1.02; 95% CI, 1-1.05). Total cholesterol levels at the end of the study were higher in new microalbuminuric (group I) than normoalbuminuric patients (group II) (group I: 211.08 [34.75] mg/dl vs group II: 200.67 [30.50]; p = 0.042). CONCLUSIONS: Tobacco, blood pressure and diabetes control influences the presence and development of microalbuminuria. More studies are required to study the influence of hypercholesterolemia.

A descriptive study of the characteristics of differentiated thyroid cancer in Catalonia during the period 1998-2012. The CECaT registry.

INTRODUCTION: The consortium for the study of thyroid cancer (CECaT), including 20 hospitals and one research institute, was recently created in Catalonia (Spain). One of the first initiatives of the group was to perform a descriptive analysis of the characteristics of patients with differentiated thyroid carcinoma (DTC). PATIENTS AND METHODS: The cohort included 1,855 patients from 11 hospitals treated over a period of 15 years (1998-2012). RESULTS: In this series, 1.470 (79.2%) patients were women. Mean age was 47.7 (15.7) years old. Age was significantly higher in male than in female patients, 49.3 (15) versus 47.3 (15.8); p=0.02. Papillary thyroid carcinoma accounted for 88.9% of cases. Mean tumor size was 21.5 (16) mm, and was significantly lower in females than in males, 20.1 (14.5) mm and 26.6 (20.3) mm respectively (p<0.001). After a follow-up period of 5.5 (3.7) years, information was available for 1,355 patient, of whom 1065 (78.6%) were free of disease, 239 (17.6%) had no tumor persistence, and 51 (3.8) % had died. The risk of persistent or recurrent disease was significantly associated to older age at diagnosis, male gender, larger tumor size, lymph node metastases at surgery, no signs of thyroiditis in the remaining thyroid tissue, and presence of vascular and/or extraglandular invasion. CONCLUSIONS: Patient characteristics analyzed are similar to those reported in other parts of the world.

Common genetic variants in pituitary-thyroid axis genes and the risk of differentiated thyroid cancer.

Thyroid hormone receptors, THRA and THRB, together with the TSH receptor, TSHR, are key regulators of thyroid function. Alterations in the genes of these receptors (THRA, THRB and TSHR) have been related to thyroid diseases, including thyroid cancer. Moreover, there is evidence suggesting that predisposition to differentiated thyroid cancer (DTC) is related to common genetic variants with low penetrance that interact with each other and with environmental factors. In this study, we investigated the association of single nucleotide polymorphisms (SNPs) in the THRA (one SNP), THRB (three SNPs) and TSHR (two SNPs) genes with DTC risk. A case-control association study was conducted with 398 patients with sporadic DTC and 479 healthy controls from a Spanish population. Among the polymorphisms studied, only THRA-rs939348 was found to be associated with an increased risk of DTC (recessive model, odds ratio=1.80, 95% confidence interval=1.03-3.14, P=0.037). Gene-gene interaction analysis using the genotype data of this study together with our previous genotype data on TG and TRHR indicated a combined effect of the pairwises: THRB-TG (P interaction=0.014, THRB-rs3752874 with TG-rs2076740; P interaction=0.099, THRB-rs844107 with TG-rs2076740) and THRB-TRHR (P interaction=0.0024, THRB-rs3752874 with TRHR-rs4129682) for DTC risk in a Spanish population. Our results confirm that THRA is a risk factor for DTC, and we show for the first time the combined effect of THRB and TG or TRHR on DTC susceptibility, supporting the importance of gene-gene interaction in thyroid cancer risk.

Possible role of the WDR3 gene on genome stability in thyroid cancer patients.

The role of the WDR3 gene on genomic instability has been evaluated in a group of 115 differentiated thyroid cancer (DTC) patients. Genomic instability has been measured according to the response of peripheral blood lymphocytes to ionizing radiation (0.5 Gy). The response has been measured with the micronucleus (MN) test evaluating the frequency of binucleated cells with MN (BNMN), both before and after the irradiation. No differences between genotypes, for the BNMN frequencies previous the irradiation, were observed. Nevertheless significant decreases in DNA damage after irradiation were observed in individuals carrying the variant alleles for each of the three genotyped SNPs: rs3754127 [-8.85 (-15.01 to -2.70), P<0.01]; rs3765501 [-8.98 (-15.61 to -2.36), P<0.01]; rs4658973 [-8.70 (-14.94 to -2.46), P<0.01]. These values correspond to those obtained assuming a dominant model. This study shows for the first time that WDR3 can modulate genome stability.

Are thyroid cancer patients sensitive to ionising radiation?

PURPOSE: To determine the ionising radiation sensitivity of peripheral blood lymphocytes in a group of differentiated thyroid cancer (DTC) patients. MATERIAL AND METHODS: A total of 53 thyroid cancer patients (26 women and 27 men) and 50 donors (23 women and 27 men) were included in the study. The cytokinesis-block micronucleus assay (CBMN) in G0 peripheral blood lymphocytes was carried out using the cytochalasin B technique. Four cultures were established per each donor, two were irradiated with 0.5 Gy 137Cs g-rays, while the other two remained untreated. RESULTS: No significant differences were observed in the frequency of binucleated cells with micronuclei (BNMN) between patients and controls, for both spontaneous and after the irradiation frequencies. Nevertheless, a positive and significant correlation was found between the frequencies of both spontaneous and after irradiation DNA damage, for control and patient groups. CONCLUSIONS: We have found that DTC patients do not present particular sensitivity to ionising radiation when an in vitro treatment is performed in G0 stage of the cell cycle, but this result does not discard the hypothesis about an increased sensitivity in other stages of the cell cycle in DTC patients.

Common variants of the thyroglobulin gene are associated with differentiated thyroid cancer risk.

BACKGROUND: Genetic factors are important in thyroid cancer susceptibility. Recently, it has been reported that there are associations of certain chromosome regions with thyroid cancer. In this case-control study, we sought to determine whether there is an association between differentiated thyroid cancer (DTC) and variants in regions of chromosome 8q. METHODS: We used a case-control association design in a population of 877 individuals (398 patients with sporadic DTC and 479 healthy controls). The iPLEX technology was applied to analyze seven single-nucleotide polymorphisms (SNPs) in chromosome 8q: two SNPs that map at 8q24, previously reported as risk markers in different types of cancer, two SNPs in the thyrotropin-releasing hormone receptor gene (TRHR), and three SNPs in the thyroglobulin gene (TG). Risk assessment was done by unconditional regression analysis. RESULTS: The two SNPs that map at 8q24, rs6983267 and rs1447295, and the two TRHR polymorphisms showed no association with DTC. No association was also found for the exon 33 TG polymorphism. The two TG polymorphisms in the exon 10-12 cluster, however, were associated with an increased risk of DTC (dominant model odds ratio = 1.80, 95% confidence interval = 1.30-2.50, p < 0.001). CONCLUSIONS: In this study, we show for the first time that the TG gene is a susceptibility factor for thyroid cancer. Although these conclusions are based on a large population, additional studies are warranted to support these data.

WDR3 gene haplotype is associated with thyroid cancer risk in a Spanish population.

BACKGROUND: A member of the genes encoding WD-repeat proteins, the WDR3 gene, maps in the 1p12 region. This region was shown to be associated with thyroid cancer susceptibility in a previous work. In this study we aim to evaluate the contribution of WDR3 to thyroid cancer risk. METHODS: A case-control association study was performed in a total of 402 patients and 479 control subjects from a Spanish population. In the initial phase of the study, 10 single-nucleotide polymorphisms covering the WDR3 region were genotyped in a small group (157 patients and 118 control subjects); next, three of the initial single-nucleotide polymorphisms were further genotyped in the overall population. In addition, WDR3 expression was investigated in 10 thyroid cancer cell lines by RT-PCR and Western blot. RESULTS: Haplotype analysis revealed that combination of certain WDR3 variants, such as haplotype CAT, increases the risk of thyroid cancer (odds ratio = 1.85, 95% confidence interval = 0.97-3.55, p = 0.063). Further, both messenger RNA transcription and protein expression of WDR3 were altered in human thyroid cancer cells. CONCLUSION: These results indicate for the first time that WDR3 is a risk factor to thyroid cancer, suggesting its implication in the etiology of thyroid cancer.

[Factors predictive of cardiovascular disease in patients with type-2 diabetes and hypercholesterolemia. ESODIAH study]. / Factores predictivos del riesgo de enfermedad cardiovascular en los pacientes con diabetes tipo 2 e hipercolesterolemia. Estudio ESODIAH.

INTRODUCTION AND OBJECTIVES: We investigated the pattern of cardiovascular disease and the factors that predict such disease in outpatients with type-2 diabetes and hypercholesterolemia. METHODS: This prospective open observational study included outpatients of both sexes (mean age 62 [8] years) with type-2 diabetes and hypercholesterolemia. Clinical manifestations of cardiovascular disease (e.g., angina, myocardial infarction, stroke and peripheral arterial disease), glucose and HbA1c levels, and cardiovascular risk factors were recorded every 4 months throughout the 2-year follow-up period. Overall, 838 patients completed follow-up. RESULTS: During follow-up, 81 patients (9.6%) presented with a cardiovascular event, nine of which were fatal. Cardiovascular events were more frequent in patients with a history of an ischemic condition than in those without: 58 of 258 (22.5%) and 23 of 579 (4%), respectively (P<.01). Previous angina or myocardial infarction was the strongest predictor of cardiovascular risk (relative risk [RR]=4.08, 95% confidence interval [CI] 2.39-6.95), followed by previous stroke (RR=2.96, 95% CI 1.26-6.93), high low-density lipoprotein (LDL)-cholesterol level > or =135 mg/dL (RR=2.79, 95% CI 1.56-5.01), peripheral arterial disease (RR=2.44, 95% CI 1.27-4.68), a high HbA1c level (RR=2.08, 95% CI 1.22-3.57), and obesity (RR=1.69, 95% CI 1.0-2.86). CONCLUSIONS: The incidence of cardiovascular disease in this southern European population of patients with type-2 diabetes and hypercholesterolemia was high. A history of an ischemic condition and a high LDL-cholesterol level during follow-up were the strongest predictors of cardiovascular disease.

Potential role of interleukin-18 in liver disease associated with insulin resistance.

OBJECTIVE: Interleukin (IL)-18 has been associated with obesity and insulin resistance, both risk factors for the development of liver disease, but the role of IL-18 in liver disease associated with insulin resistance is presently unknown. We hypothesized that circulating IL-18 would be related to serum concentrations of liver chemistry tests (LCTs) in apparently healthy subjects and wished to study whether this correlation was dependent on insulin sensitivity (S(I)). RESEARCH METHODS AND PROCEDURES: One hundred six apparently healthy white men consecutively enrolled in a cross-sectional, population-based study dealing with S(I) in men were studied, and S(I) (minimal model analysis), LCTs (colorimetry), and IL-18 serum concentrations (immunoassay) were assessed. RESULTS: Compared with subjects in the lowest quartile for serum IL-18, subjects in the highest quartile exhibited increased serum triglycerides and decreased S(I), in addition to higher serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) (all p < 0.05). The direct association between both ALT and AST and IL-18 was further confirmed by examining the distribution of serum IL-18 by quartiles of ALT and AST. Subjects in the highest quartile for serum ALT and AST had higher IL-18 concentrations compared with subjects in the lowest quartile for these LCTs (both p = 0.01). In multiple regression analysis, IL-18, but not S(I), was an independent predictor of serum concentrations of ALT and AST, explaining 7% and 4% of their variance, respectively. DISCUSSION: In summary, IL-18 serum concentrations are associated in apparently healthy humans with plasma concentrations of various LCTs. IL-18 could contribute to the development of liver disease associated with insulin resistance.