Teresa C. Ferreira

Association of Polymorphisms in Genes of the Homologous Recombination DNA Repair Pathway and Thyroid Cancer Risk

BACKGROUND Ionizing radiation exposure has been pointed out as a risk factor for thyroid cancer. The double-strand breaks induced by this carcinogen are usually repaired by homologous recombination repair pathway, a pathway that includes several polymorphic genes. Since there is a scarcity of data about the involvement of these gene polymorphisms in thyroid cancer susceptibility, we carried out a case-control study in a Caucasian Portuguese population. METHODS We genotyped 109 patients and 217 controls for the XRCC3 T241M, XRCC2 R188H, NBS1 E185Q, and RAD51 Ex1-59G>T polymorphisms to evaluate their potential main effects on risk for this pathology. RESULTS The results obtained showed that for the RAD51 Ex1-59G>T polymorphism, the homozigosity for the variant allele was associated with an almost significant increase of the odds ratio (OR) (adjusted OR = 1.9; confidence interval 95%: 1.0-3.5; p = 0.057). Additionaly, when the XRCC3 T241M data were analyzed concerning the presence of at least one wild-type allele, we observed that individuals homozygous for the variant allele had a higher risk for thyroid cancer (adjusted OR = 2.0; confidence interval 95%: 1.1-3.6; p = 0.026). When the data were analyzed according to the number of RAD51 Ex1-59G>T and XRCC3 T241M variant alleles, the coexistence of three or more variant alleles in either gene was associated to a significant higher risk (three variant alleles: adjusted OR = 2.9, p = 0.036; four variant alleles: adjusted OR = 8.0, p = 0.006). CONCLUSIONS Since XRCC3 is involved in the assembly and stabilization of RAD51 protein multimers at double-strand break sites, we cannot exclude that the interaction of both polymorphisms can lead to a decreased DNA repair capacity and consequently increased risk for thyroid cancer.

Association of Polymorphisms in ERCC2 Gene with Non-Familial Thyroid Cancer Risk

The ERCC2 protein is an evolutionary conserved ATP-dependent helicase that is associated with a TFIIH transcription factor complex and plays an important role in nucleotide excision repair. Mutations in this gene are responsible for xeroderma pigmentosum and also for Cocayne syndrome and trichothiodystrophy. Several single nucleotide polymorphisms have been identified in the ERCC2 locus. Among them, a G23591A polymorphism in the codon 312 results in an Asp → Asn substitution in a conserved region and a A35931C polymorphism in the codon 751 results in a Lys → Gln substitution. Because these polymorphisms have been associated with an increased risk for several types of cancers, we carried out an hospital based case-control study in a Caucasian Portuguese population to evaluate the potential role of these polymorphisms on the individual susceptibility to thyroid cancer. The results obtained did not reveal a significant association between each individual polymorphism studied (G23591A and A35931C) and an increased thyroid cancer risk, but individuals homozygous for non-wild-type variants are overrepresented in patients group. The evaluation of the different haplotypes generated by these polymorphisms showed that individuals simultaneously homozygous for rare variants of both polymorphisms have an increased risk for thyroid cancer [adjusted odds ratio (OR) 3.084; 95% confidence interval (95% CI), 1.347-7.061; P = 0.008] and for papillary thyroid–type tumors (adjusted OR, 2.997; 95% CI, 1.235-7.272; P = 0.015) but not for follicular thyroid–type tumors. These results suggest that genetic polymorphisms in this gene might be associated with individual susceptibility towards thyroid cancer, mainly papillary-type tumors, but larger studies are required to confirm these results.

Polymorphisms in base excision repair genes and thyroid cancer risk

Thyroid cancer (TC) is the most frequent endocrine malignancy, accounting however for only 1-2% of all human cancers, and the best-established risk factor for TC is radiation exposure, particularly during childhood. Since the BER pathway seems to play an important role in the repair of DNA damage induced by IR and other genotoxicants, we carried out a hospital-based case-control study in order to evaluate the potential modifying role of 6 BER polymorphisms on the individual susceptibility to non-familial TC in 109 TC patients receiving iodine-131, and 217 controls matched for age (± 2 years), gender and ethnicity. Our results do not reveal a significant involvement of XRCC1 Arg194Trp and Arg399Gln, OGG1 Ser326Cys, APEX1 Asp148Glu, MUTYH Gln335His and PARP1 Val762Ala polymorphisms on the individual susceptibility towards TC, mostly in agreement with the limited available evidence. By histological stratification analysis, we observed that the association between the presence of heterozygosity in the MUTYH Gln335His polymorphism and TC risk almost reached significance for the papillary subtype of TC. This was the first time that the putative association between this polymorphism and TC susceptibility was evaluated. However, since the sample size was modest, the possibility of a type I error should not be excluded and this result should, therefore, be interpreted with caution. More in depth studies involving larger populations should be pursued in order to further clarify the potential usefulness of the MUTYH Gln335His genotype as a predictive biomarker of susceptibility to TC and the role of the remaining BER polymorphisms on TC susceptibility.

Early Diagnosis of Invasive Aspergillosis in Neutropenic Patients. Comparison between Serum Galactomannan and Polymerase Chain Reaction.

Background Invasive aspergillosis (IA) is a major cause of morbidity and mortality in profoundly neutropenic patients, so early diagnosis is mandatory. Aim Consecutive patients with hematological malignancies undergoing intensive chemotherapy were screened for IA with two different methods which were compared. Methods From October 2000 to August 2003 we tested 1311 serum samples from 172 consecutive patients with a polymerase chain reaction assay and between April 2005 and April 2008 we tested 806 serum samples from 169 consecutive patients with a Galactomannan (GM) test. Bronchoalveolar (BAL) samples were obtained whenever the patients condition allowed and tested with either method. Results: The serum PCR assay had a sensitivity of 75.0% and a specificity of 91.9% and the serum GM assay had a sensitivity of 87.5% and a specificity of 93.1%, (P > 0.05). The presence of two or more consecutive positive serum samples was predictive of IA for both assays. BAL GM/PCR was positive in some patients without serum positivity and in patients with 2 or more positive serum GM/PCR. Conclusions: No significant differences between the 2 serum tests were found. The GM assay has the advantage of being standardized among several laboratories and is incorporated in the criteria established by the European Organization for Research and Treatment of Cancer/Invasive Fungal Infections Cooperative Group and the National Institute of Allergy and Infectious Diseases Mycosis Study Group (EORTC/MSG), however is much more expensive. BAL GM and PCR sampling aids in IA diagnosis but needs further validation studies to differentiate between colonization and true infection in cases where serum GM or PCR are negative.

No evidence of increased chromosomal aberrations and micronuclei in lymphocytes from nonfamilial thyroid cancer patients prior to radiotherapy

The relationship between the presence of high frequencies of chromosomal aberrations in peripheral lymphocytes and predisposition to cancer has been suggested for some cancer diseases. In nonfamilial thyroid cancer, the few reports available are equivocal. The aim of this study was to assess the possible chromosomal instability in peripheral blood lymphocytes from 22 patients suffering from nonfamilial thyroid cancer. For this purpose, 2 classic cytogenetic assays, the chromosomal aberrations assay and cytokinesis-blocked micronucleus assay, were chosen. The frequency of chromosomal aberrations excluding gaps (%) was 1.68 +/- 1.39 (mean value +/- SD) for the patients group versus 2.20 +/- 1.87 for the control group. The frequency of binucleated lymphocytes with micronuclei ( per thousand) was 5.41 +/- 3.51 (mean value +/- SD) for the patients group versus 5.37 +/- 3.21 for the control group. The results obtained revealed no significant differences between both groups. The present study reinforces the idea that constitutional chromosomal instability in peripheral blood lymphocytes is not visible in nonfamilial thyroid carcinomas.

Possible transient adaptive response to mitomycin C in peripheral lymphocytes from thyroid cancer patients after iodine-131 therapy.

Our study attempted to assess the possible induction and persistence of an adaptive response in lymphocytes of thyroidectomized thyroid cancer patients treated with 131I (2,590 MBq, corresponding to whole body doses in the range of 200–300 mGy), to a testing dose of mitomycin C (MMC) in vitro. The cytogenetic endpoint studied was the induction of micronuclei in cytokinesis‐blocked peripheral blood lymphocytes, immediately before treatment and 1, 6 and 24 months after therapy. One month after therapy, induction of micronucleated cytokinesis‐blocked lymphocytes (‰) by MMC was lower (34.6 ± 7.7) than before therapy (52.1 ± 5.0). In 7 of 11 patients this reduction was significant. However, at 6 months, induction of micronuclei was markedly higher (133.1 ± 13.6). This significant increase was observed regardless of the decrease at 1 month. At 24 months, the frequency of micronucleated cells decreased (84.8 ± 5.5), but remained higher than before treatment. The results obtained 1 month after therapy could reflect adaptation due to radiation, or a higher rate of early apoptosis or cell death, with bone marrow suppression, visible as a lower response in vitro towards MMC. At 6 months, recovery of the lymphocyte population may occur, and higher responses to MMC in vitro could reflect higher chromosomal instability in the previously irradiated stem cells with a concomitant disappearance of adaptation, whereas at 24 months the results show a tendency to return to pretherapy values.

Bone scan usefulness in patients with painful hip or knee prosthesis: 10 situations that can cause pain, other than loosening and infection

In recent years, with the higher median life expectancy, the number of hip and knee replacements has increased. Clinical examination and morphological studies are essential to evaluate patients with a painful arthroplasty. Nuclear medicine examinations also play an important role, their main usefulness being the exclusion of prosthesis complications. Nevertheless, conventional examinations, namely bone scan and white blood cell scintigraphy, can also identify complications, such as loosening and infection. This study describes the normal and pathologic patterns of a bone scan and exemplifies ten common situations that can cause pain in patients with hip or knee arthroplasty, other than loosening and infection, which can be disclosed on a bone scintigraphy. The ten situations that should be considered and looked for when analysing a bone scan are: referred pain, patellofemoral pain syndrome, fractures, fissures, abscess/haematoma, bone insert behaviour, heterotopic ossification, greater trochanter pseudarthrosis, osteoarthritis extension in a knee with an unicompartmental prosthesis, and systemic disease with bone involvement.

Mismatch repair single nucleotide polymorphisms and thyroid cancer susceptibility

Thyroid cancer (TC) is the most common endocrine malignancy and its incidence continues to rise worldwide. Ionizing radiation exposure is the best established etiological factor. Heritability is high; however, despite valuable contribution from recent genome-wide association studies, the current understanding of genetic susceptibility to TC remains limited. Several studies suggest that altered function or expression of the DNA mismatch repair (MMR) system may contribute to TC pathogenesis. Therefore, the present study aimed to evaluate the potential role of a panel of MMR single nucleotide polymorphisms (SNPs) on the individual susceptibility to well-differentiated TC (DTC). A case-control study was performed involving 106 DTC patients and 212 age- and gender-matched controls, who were all Caucasian Portuguese. Six SNPs present in distinct MMR genes (MLH1 rs1799977, MSH3 rs26279, MSH4 rs5745325, PMS1 rs5742933, MLH3 rs175080 and MSH6 rs1042821) were genotyped through TaqMan® assays and genotype-associated risk estimates were calculated. An increased risk was observed in MSH6 rs1042821 variant homozygotes [adjusted odds ratio (OR)=3.42, 95% CI: 1.04-11.24, P=0.04, under the co-dominant model; adjusted OR=3.84, 95% CI: 1.18-12.44, P=0.03, under the recessive model]. The association was especially evident for the follicular histotype and female sex. The association was also apparent when MSH6 was analysed in combination with other MMR SNPs such as MSH3 rs26279. Interestingly, two other SNP combinations, both containing the MSH6 heterozygous genotype, were associated with a risk reduction, suggesting a protective effect for these genotype combinations. These data support the idea that MMR SNPs such as MSH6 rs1042821, alone or in combination, may contribute to DTC susceptibility. This is coherent with the limited evidence available. Nevertheless, further studies are needed to validate these findings and to establish the usefulness of these SNPs as genetic susceptibility biomarkers for DTC so that, in the near future, cancer prevention policies may be optimized under a personalized medicine perspective.

Metastatic differentiated thyroid cancer with undetectable serum thyroglobulin: diagnostic, management and follow-up challenges

1. Westburey C, Vini L, Fisher C, Harmer C. Recurrent differentiated thyroid cancer without elevation of serum thyroglobulin. Thyroid 2000;10(2):171-176 2. Giovanella L, Clark P, Chiovato L, Duntas L, Elisei R, et al. Thyroglobulin measurement using highly sensitive assays in patients with differentiated thyroid cancer: a clinical position paper. Eur J Endocrinol 2014;171:R33-R46 Figure 2: Post-radioiodine whole-body scan showing iodine-avid lung lesions (A); FDG-PET scan showing uptake in the lung metastasis (B). A

P67. STRUMA OVARII MALIGNO EM IDADE FÉRTIL: 2 CASOS CLÍNICOS

Introdução: Realizou-se um estudo prospetivo da forma de apresentação clínica e epidemiológica do Bócio nos doentes da Consulta Externa de Cirurgia do Hospital Geral do Huambo (HGH), durante o período de 1 de Julho a 31 de Outubro de 2010. O diagnóstico foi realizado com base na Inspeção e Palpação. Foram classificados em 3 graus segundo a OMS. Métodos: Variáveis estudadas: distribuição por grupo etário, sexo, tempo de evolução, tempo de evolução por município; grau, grau/município, grau/grupo etário. Foram observados 108 doentes com bócio. Resultados: Registou-se maior frequência de bócio no grupo etário dos 31-40 anos com 36 casos (33,30%) seguido do grupo 41-50 anos com 30 casos (27,80%). Todos doentes, 108 (100%), eram do sexo feminino. Foram observados 48 doentes (44,40%) provenientes do Bailundo e 40 doentes (35,1%) eram do município sede, o Huambo. Os doentes com evolução do bócio de 6-10 anos, 40 doentes (37%) constituíram o grupo mais observado nas consultas externas. Entre estes, 19 doentes (45,7%) eram provenientes do município do Bailundo. Foram observados mais casos de bócio do Grau III, 51 doentes (47%). O bócio de Grau II e III ocorreu com mais frequência em doentes provenientes do município do Bailundo, 29 doentes (26,8%). O bócio de grau III foi mais frequente nos doentes do grupo etário > 61 anos com 9 casos (100%) Conclusão: 1. Elevada frequência de bócio em mulheres entre os 30-50 anos de idade. 2. O Bócio grau III ocorreu em maior percentagem nos grupos etários mais avançados. 3. Elevada frequência de bócio nos doentes provenientes do município do Bailundo. 4. Maior frequência de bócio de graus mais elevados em doentes provenientes do Bailundo.