Adélia Mendes

TERT Promoter Mutations in Skin Cancer: The Effects of Sun Exposure and X-Irradiation

The reactivation or reexpression of telomerase (TERT) is a widespread feature of neoplasms. TERT promoter mutations were recently reported that were hypothesized to result from UV radiation. In this retrospective study, we assessed TERT promoter mutations in 196 cutaneous basal cell carcinomas (BCCs), including 102 tumors from X-irradiated patients, 94 tumors from patients never exposed to ionizing radiation treatment, and 116 melanomas. We sought to evaluate the effects of UV and X-ray irradiation on TERT mutation frequency. TERT mutations were detected in 27% of BCCs from X-irradiated patients, 51% of BCCs from nonirradiated patients, and 22% of melanoma patients. TERT mutations were significantly increased in non-X-irradiated BCC patients compared with X-irradiated BCC patients; the mutations also presented a different mutation signature. In nonirradiated patients, TERT mutations were more frequent in BCCs of sun-exposed skin, supporting a possible causative role of UV radiation. In melanoma, TERT promoter mutations were generally restricted to intermittent sun-exposed areas and were associated with nodular and superficial spreading subtypes, increased thickness, ulceration, increased mitotic rate, and BRAFV600E mutations. Our results suggest that various carcinogenic factors may cause distinct TERT promoter mutations in BCC and that TERT promoter mutations might be associated with a poorer prognosis in melanoma.

A polymorphism in the promoter region of the selenoprotein S gene (SEPS1) contributes to Hashimoto's thyroiditis susceptibility.

CONTEXTnThe association between selenium and inflammation and the relevance of selenoproteins in follicular thyroid cell physiology have pointed to a putative role of selenoproteins in the pathogenesis of autoimmune thyroid diseases.nnnOBJECTIVEnThe aim of this study was to evaluate the role of a promoter variation in SEPS1, the selenoprotein S gene, in the risk for developing Hashimotos thyroiditis (HT).nnnDESIGNnA case-control study was performed to assess the association of genetic variation in the SEPS1 gene (SEPS1 -105G/A single-nucleotide polymorphism, rs28665122) and HT.nnnSETTINGnThe study was conducted in north Portugal, Porto, in the period of 2007-2013.nnnPATIENTS OR OTHER PARTICIPANTSnA total of 997 individuals comprising 481 HT patients and 516 unrelated controls were enrolled in the study.nnnMAIN OUTCOME MEASURESnGenetic variants were discriminated by real-time PCR using TaqMan single-nucleotide polymorphism genotyping assays.nnnRESULTSnThere is a significant association between the SEPS1 -105 GA and AA genotypes and HT [odds ratio (OR) 2.24, confidence interval (CI) 1.67-3.02, P < 5.0 × 10(-7), and OR 2.08, CI 1.09-3.97, P = .0268, respectively]. The A allele carriers are in higher proportion in the patient group than in the control population (46.2% vs 28.1%, P < 5.0 × 10(-7)) with an OR (CI) of 2.22 (1.67-2.97). The proportion of patients carrying the A allele is significantly higher in male patients with HT, representing a 3.94 times increased risk (P = 7.9 × 10(-3)).nnnCONCLUSIONnOur findings support the existence of a link between SEPS1 promoter genetic variation and HT risk.

Fluoroquinolone–metal complexes: A route to counteract bacterial resistance?

Microbial resistance to antibiotics is one of the biggest public health threats of the modern world. Antibiotic resistance is an area of much clinical relevance and therefore research that has the potential to identify agents that may circumvent it or treat resistant infections is paramount. Solution behavior of various fluoroquinolone (FQ) complexes with copper(II) in the presence and absence of 1,10-phenanthroline (phen) was studied in aqueous solution, by potentiometry and/or spectrophotometry, and are herein described. The results obtained showed that under physiological conditions (micromolar concentration range and pH7.4) only copper(II):FQ:phen ternary complexes are stable. Hence, these complexes were synthesised and characterised by means of UV-visible and IR spectroscopy, elemental analysis and single-crystal X-ray diffraction. In these complexes, the FQ acts as a bidentate ligand that coordinates the metal cation through the carbonyl and carboxyl oxygen atoms and phen coordinates through two N-atoms forming the equatorial plane of a distorted square-pyramidal geometry. The fifth position of the penta-coordinated Cu(II) centre is generally occupied axially by an oxygen atom from a water molecule or from a nitrate ion. Minimum inhibitory concentration (MIC) determinations of the complexes and comparison with free FQ in various E. coli strains indicate that the Cu-complexes are as efficient antimicrobials as the free antibiotic. Moreover, results strongly suggest that the cell intake route of both species is different supporting, therefore, the complexes suitability as candidates for further biological testing in FQ-resistant microorganisms.

Polymorphisms in the TNFA and IL6 Genes Represent Risk Factors for Autoimmune Thyroid Disease

Background Autoimmune thyroid disease (AITD) comprises diseases including Hashimotos thyroiditis and Graves disease, both characterized by reactivity to autoantigens causing, respectively, inflammatory destruction and autoimmune stimulation of the thyroid-stimulating hormone receptor. AITD is the most common thyroid disease and the leading form of autoimmune disease in women. Cytokines are key regulators of the immune and inflammatory responses; therefore, genetic variants at cytokine-encoding genes are potential risk factors for AITD. Methods Polymorphisms in the IL6-174 G/C (rs1800795), TNFA-308 G/A (rs1800629), IL1B-511 C/T (rs16944), and IFNGR1-56 T/C (rs2234711) genes were assessed in a case-control study comprising 420 Hashimotos thyroiditis patients, 111 Graves disease patients and 735 unrelated controls from Portugal. Genetic variants were discriminated by real-time PCR using TaqMan SNP genotyping assays. Results A significant association was found between the allele A in TNFA-308 G/A and Hashimotos thyroiditis, both in the dominant (ORu200a=u200a1.82, CIu200a=u200a1.37–2.43, p-valueu200a=u200a4.4×10−5) and log-additive (ORu200a=u200a1.64, CIu200a=u200a1.28–2.10, p-valueu200a=u200a8.2×10−5) models. The allele C in IL6-174 G/C is also associated with Hashimotos thyroiditis, however, only retained significance after multiple testing correction in the log-additive model (ORu200a=u200a1.28, CIu200a=u200a1.06–1.54, p-valueu200a=u200a8.9×10−3). The group with Graves disease also registered a higher frequency of the allele A in TNFA-308 G/A compared with controls both in the dominant (ORu200a=u200a1.85, CIu200a=u200a1.19–2.87, p-valueu200a=u200a7.0×10−3) and log-additive (ORu200a=u200a1.69, CIu200a=u200a1.17–2.44, p-valueu200a=u200a6.6×10−3) models. The risk for Hashimotos thyroiditis and Graves disease increases with the number of risk alleles (OR for two risk alleles is, respectively, 2.27 and 2.59). Conclusions This study reports significant associations of genetic variants in TNFA and IL6 with the risk for AITD, highlighting the relevance of polymorphisms in inflammation-related genes in the etiopathogenesis of AITD.

Thyroid and parathyroid tumours in patients submitted to X-ray scalp epilation during the tinea capitis eradication campaign in the North of Portugal (1950–1963)

Tinea capitis attained epidemical proportions in the fifth and sixth decades in Portugal, as in other countries. Before starting the utilization of griseofulvin in 1959, the best approach to treat tinea capitis infection was X-ray scalp epilation combined with topical antimycotic ointments. A long-term side effect of this therapy is thyroid disease, namely thyroid cancer; data on parathyroid lesions (hyperplasia, adenoma and carcinoma) are scarce. We observed clinically 1,375 individuals irradiated in childhood for tinea capitis treatment in the North of Portugal with the main purpose of evaluating thyroid and parathyroid tumours as possible sequelae of the irradiation treatment. For each individual, a cervical ultrasound and a serum calcium measurement were proposed. Fine needle aspiration cytology was suggested whenever ultrasound thyroid nodules presented suspicious features. We observed a 54xa0% frequency of thyroid nodules and a 2.8xa0% frequency of thyroid carcinoma (38/1,375). Nineteen of the 38 (50xa0%) carcinomas were diagnosed by us, whereas the remaining 19 carcinomas had been diagnosed and treated prior to our observation. The carcinomas were significantly more frequent in women than in men. Benign excised lesions were also significantly more frequent in women and in patients irradiated at younger ages. Seven women, considered asymptomatic until our clinical observation, had laboratory signs of hyperparathyroidism. The data we have obtained, namely high thyroid cancer frequency, corroborate previous data from childhood irradiated cohorts and highlight the need for the close follow-up of these populations in order to identify and treat early undiagnosed head and neck lesions. No evidence of increased parathyroid disease was found in this cohort of head and neck X-irradiated patients.

Genetic alterations in thyroid tumors from patients irradiated in childhood for tinea capitis treatment

OBJECTIVEnExposure to ionizing radiation at young age is the strongest risk factor for the occurrence of papillary thyroid carcinoma (PTC). RET/PTC rearrangements are the most frequent genetic alterations associated with radiation-induced PTC, whereas BRAF and RAS mutations and PAX8-PPARG rearrangement have been associated with sporadic PTC. We decided to search for such genetic alterations in PTCs of patients subjected in childhood to scalp irradiation.nnnDESIGNnWe studied 67 thyroid tumors from 49 individuals irradiated in childhood for tinea capitis scalp epilation: 36 malignant (12 cases of conventional PTC (cPTC), two cPTC metastases, 20 cases of follicular variant PTC (FVPTC), one oncocytic variant of PTC and one follicular carcinoma) and 31 follicular thyroid adenomas.nnnMETHODSnThe lesions were screened for the BRAF(V600E) and NRAS mutations and for RET/PTC and PAX8-PPARG rearrangements.nnnRESULTSnBRAF(V600E) mutation was detected in seven of 14 (50%) cPTC and two of 20 FVPTC (10%) (P=0.019). NRAS mutation was present in one case of FVPTC (5%). RET/PTC1 rearrangement was found, by RT-PCR, in one of 17 cases (5.9%) and by fluorescence in situ hybridization in two of six cases (33%). PAX8-PPARG rearrangement was not detected in any carcinoma. None of the follicular adenomas presented any of the aforementioned genetic alterations.nnnCONCLUSIONSnThe prevalence of BRAF(V600E) mutation in our series is the highest reported in series of PTCs arising in radiation-exposed individuals. The prevalence of RET/PTC1 rearrangement fits with the values recently described in a similar setting.

TERT promoter mutations: A genetic signature of benign and malignant thyroid tumours occurring in the context of tinea capitis irradiation

OBJECTIVEnThe aim of this study is to evaluate the frequency and molecular characteristics of TERTp mutations in thyroid adenomas and carcinomas occurring in the low-dose radiation exposure tinea capitis setting.nnnDESIGN AND METHODSnTwenty-seven patients with 34 well-differentiated thyroid carcinomas and 28 patients with 29 follicular adenomas diagnosed in a Portuguese tinea capitis cohort were studied. Blood samples were obtained from all the patients. Screening for TERTp mutations was performed by PCR amplification followed by Sanger sequencing. A series of 33 sporadic thyroid adenomas was used as control.nnnRESULTSnTERTp mutations were detected in six of the 28 patients with adenoma (21.4%) and in four of the 27 patients with carcinoma (14.8%). Three tumours (two carcinomas and one adenoma) had the tandem mutation -124/-125 GG>AA (30.0%), whereas the remaining seven had the -124Gu2009>u2009A. The 20.7% frequency of TERTp mutations in adenomas contrasts with the absence of mutations in the adenomas from the control group and from most series on record, whereas the one found in carcinomas (11.8%) is similar to those reported in the literature for sporadic carcinomas.nnnCONCLUSIONnTERTp mutations, including the tandem mutation -124/-125 GG>AA not described previously in thyroid tumours, appear to represent a genetic signature for thyroid tumours in patients submitted to low-dose X-ray irradiation. The high frequency of TERTp mutations in the adenomas of our cohort contrasts with their absence in sporadically occurring, as well as in adenomas of the Chernobyl series.

Mitochondrial D310 D-Loop instability and histological subtypes in radiation-induced cutaneous basal cell carcinomas

BACKGROUNDnBasal cell carcinoma (BCC) is the most frequent skin cancer. An elevated prevalence of BCC has been associated with radiation, namely after the Tinea capitis epilation treatment, being these tumors described as more aggressive. Mitochondrial DNA (mtDNA) mutations have been reported in many human tumors, but their occurrence in BCC is poorly documented.nnnOBJECTIVEnThe purpose of this work was to evaluate BCC histological subtypes in individuals subjected to X-ray epilation for Tinea capitis treatment when compared to non-irradiated patients. Moreover we also wanted to evaluate mitochondrial D-Loop instability in both groups of BCCs in order to compare the frequency of D-Loop mutations in post-irradiation BCC versus sporadic BCC.nnnMETHODSn228 histological specimens corresponding to BCCs from 75 irradiated patients and 60 non-irradiated patients were re-evaluated for histological subtype. Subsequently, we sequenced the D-Loop 310 repeat in blood, oral mucosa, tumor lesions and, whenever available, non-tumoral adjacent tissue from these patients.nnnRESULTSnThe infiltrative subtype of BCC, considered to be more aggressive, was significantly more frequent in irradiated patients. BCC D-Loop D310 mutation rate was significantly higher in irradiated BCCs than in the non-irradiated ones. Moreover, it was associated with a higher irradiation dose. The presence of mtDNA heteroplasmy in patients blood was associated with a higher mutation rate in the BCCs suggesting that a more unstable genotype could predispose to mtDNA somatic mutation.nnnCONCLUSIONSnOur results suggest that radiation-induced BCCs may be considered to be more aggressive tumors. Further studies are needed to clarify the role of mtDNA D-Loop mutations in tumors from irradiated patients.

IL6-174 G>C Polymorphism (rs1800795) Association with Late Effects of Low Dose Radiation Exposure in the Portuguese Tinea Capitis Cohort.

Head and neck cancers, and cardiovascular disease have been described as late effects of low dose radiation (LDR) exposure, namely in tinea capitis cohorts. In addition to radiation dose, gender and younger age at exposure, the genetic background might be involved in the susceptibility to LDR late effects. The -174 G>C (rs1800795) SNP in IL6 has been associated with cancer and cardiovascular disease, nevertheless this association is still controversial. We assessed the association of the IL6-174 G>C SNP with LDR effects such as thyroid carcinoma, basal cell carcinoma and carotid atherosclerosis in the Portuguese tinea capitis cohort. The IL6-174 G>C SNP was genotyped in 1269 individuals formerly irradiated for tinea capitis. This sampling group included thyroid cancer (n = 36), basal cell carcinoma (n = 113) and cases without thyroid or basal cell carcinoma (1120). A subgroup was assessed for atherosclerosis by ultrasonography (n = 379) and included matched controls (n = 222). Genotypes were discriminated by real-time PCR using a TaqMan SNP genotyping assay. In the irradiated group, we observed that the CC genotype was significantly associated with carotid plaque risk, both in the genotypic (OR = 3.57, CI = 1.60–7.95, p-value = 0.002) and in the recessive (OR = 3.02, CI = 1.42–6.42, p-value = 0.004) models. Irradiation alone was not a risk factor for carotid atherosclerosis. We did not find a significant association of the IL6-174 C allele with thyroid carcinoma or basal cell carcinoma risk. The IL6-174 CC genotype confers a three-fold risk for carotid atherosclerotic disease suggesting it may represent a genetic susceptibility factor in the LDR context.

Is Low-Dose Radiation Exposure a Risk Factor for Atherosclerotic Disease?

Nontargeted late effects of radiation include an increased risk of cardiovascular disease, although this is still debatable in the context of low-dose radiation. Tinea capitis patients treated in childhood with X rays to induce scalp epilation received a low dose of radiation to their carotids. To better clarify this issue, we evaluated carotid atherosclerosis in a cohort of such patients treated in 1950–1963 in Portugal. A group of 454 individuals randomly chosen from previously observed Portuguese tinea capitis patients and a control group mainly composed of their spouses (n = 280) were enrolled. Cardiovascular risk factors such as waist circumference, body mass index, blood pressure and tobacco consumption, as well as biochemical measurements were obtained. Ultrasound imaging of carotid arteries for intima media thickness and stenosis evaluation were performed according to a standardized protocol. In comparison to the control group, the irradiated cohort members were significantly older, more frequently never smokers, hypertensive, and presented higher glycated hemoglobin and alkaline phosphatase levels. In addition, the irradiated cohort showed a higher frequency of carotid stenosis ≥30% than the nonirradiated group (13.9% vs. 10.7%), although this was not significant (P = 0.20). Stenosis was ≥50% in 2.9% of the irradiated group and 0.4% of the nonirradiated group (P = 0.02). Likewise, the frequency of intima media thickness ≥1 mm was significantly higher in the irradiated group (16.8% vs. 10.7%; P = 0.02). Multivariate analysis, including other cardiovascular risk factors, showed that exposure to low-dose radiation increased the risk of carotid stenosis by ≥50% [odds ratio (OR) = 8.85; P = 0.04] and intima media thickness by ≥1 mm (OR = 1.82; P = 0.02). These findings confirm that low-dose exposure is a risk factor of carotid atherosclerotic disease.