Of all malignant neoplasias affecting women, breast cancer has the highest incidence rate in Brazil. The objective of the present study was to determine the frequency of genetic modifications in families with medium and high risk for breast and ovarian cancer from different regions of Brazil. An exploratory, descriptive study was carried out on the prevalence of the BRCA1 and BRCA2 mutations in case series of high-risk families for breast and/or ovarian cancer. After heredogram construction, a blood sample was taken and DNA extraction was performed in all index cases. The protein truncation test was used to screen for truncated mutations in exon 11 of the BRCA1 gene and in exons 10 and 11 of the BRCA2 gene. Of the 612 individuals submitted to genetic testing, 21 (3.4%), 19 women and 2 men, had mutations in the BRCA1 or BRCA2 genes. Of the 19 BRCA1 mutations found in the 18 participants, 7 consisted of ins6kb mutations, 4 were 5382insC, 3 were 2156delGinsCC, 2 were 185delAG, 1 was C1201G, 1 was C3522T, and 1 was 3450del4. With respect to the BRCA2 gene, 3 mutations were found: 5878del10, 5036delA and 4232insA (one case each). The prevalence of germline mutations in the BRCA1 and BRCA2 genes found in the present study was lower than reported by other studies on high-risk Brazilian populations. The inclusion of individuals with medium risk may have contributed to the lower prevalence observed.

Acute leukemia in early childhood is biologically and clinically distinct. The particular characteristics of this malignancy diagnosed during the first months of life have provided remarkable insights into the etiology of the disease. The pro-B, CD10 negative immunophenotype is typically found in infant acute leukemia, and the most common genetic alterations are the rearrangements of the MLL gene. In addition, the TEL/AML1 fusion gene is most frequently found in children older than 24 months. A molecular study on a Brazilian cohort (age range 0-23 months) has detected TEL/AML1+ve (N = 9), E2A/PBX1+ve (N = 4), PML/RARA+ve (N = 4), and AML1/ETO+ve (N = 2) cases. Undoubtedly, the great majority of genetic events occurring in these patients arise prenatally. The environmental exposure to damaging agents that give rise to genetic changes prenatally may be accurately determined in infants since the window of exposure is limited and known. Several studies have shown maternal exposures that may give rise to leukemogenic changes. The Brazilian Collaborative Study Group of Infant Acute Leukemia has found that mothers exposed to dipyrone, pesticides and hormones had an increased chance to give birth to babies with infant acute leukemia [OR = 1.48 (95%CI = 1.05-2.07), OR = 2.27 (95%CI = 1.56-3.31) and OR = 9.08 (95%CI = 2.95-27.96)], respectively. This review aims to summarize recent clues that have facilitated the elucidation of the biology of early childhood leukemias, with emphasis on infant acute leukemia in the Brazilian population.

Um estudo de caso foi desenvolvido para avaliar a ocorrência de um agrupamento de casos de câncer em 1992, que se verificou em adultos jovens indígenas vivendo em aldeia na Amazônia, situada nas proximidades de duas linhas de transmissão de 500 kV, as quais começaram a operar em 1982. Determinaram-se os níveis sangüíneos atuais de DDT e pesticidas organofosforados, assim como a presença de metais em amostras de cabelo. A exposição a campos eletromagnéticos de freqüência extremamente baixa foi determinada durante diversas atividades diárias desenvolvidas pelos indígenas. Considerando-se a incidência de câncer em diferentes cidades brasileiras, a probabilidade de ocorrência ao acaso deste agrupamento de casos foi considerada remota (p<0,03, distribuição de Poisson). Níveis elevados de p,p'-DDT (mediana variando entre 26 e 58 ppb) foram observados nas amostras estudadas. A exposição contínua aos campos eletromagnéticos de freqüência extremamente baixa, a qual atingiu 95 mG abaixo das linhas de transmissão, foi observada em diversas oportunidades durante atividades diárias desenvolvidas pelos indígenas. Estudos observacionais futuros deveriam analisar a interação da exposição aos campos eletromagnéticos de freqüência extremamente baixa (50-60 Hz) subseqüente à exposição a agentes de iniciação tumoral no desenvolvimento de neoplasias.

A case study was carried out to explore the occurrence of a cancer cluster in 1992 among young indian adults living in an Amazonian village near two 500 kV power transmission lines that began operating a decade ago. Current blood levels of DDT and organophosphorus pesticides and metal levels in hair samples were measured. Extremely low magnetic field exposure was determined during current daily activities carried out by the Indian villagers. Taking into account the cancer incidence rates in different Brazilian cities, the probability of the occurrence of this cluster by chance was considered remote (p< 0.003, Poisson distribution). High blood levels of p,p'-DDT (median levels ranging from 26 to 58 ppb) were observed. As a whole, this community showed a pattern of low exposure to organophosphorus pesticides, and high recent exposure was only observed in a few blood samples. Continuous exposure to extremely low electromagnetic fields originated in the power transmission lines (which reached 95.0 mG under the lines) was observed on several opportunities during daily activities carried out by Indian villagers. Further observational studies should evaluate the interaction between exposure to extremely low electromagnetic fields and prior exposure to tumor initiators in cancer development.

Um estudo de caso foi desenvolvido para avaliar a ocorrência de um agrupamento de casos de câncer em 1992, que se verificou em adultos jovens indígenas vivendo em aldeia na Amazônia, situada nas proximidades de duas linhas de transmissão de 500 kV, as quais começaram a operar em 1982. Determinaram-se os níveis sangüíneos atuais de DDT e pesticidas organofosforados, assim como a presença de metais em amostras de cabelo. A exposição a campos eletromagnéticos de freqüência extremamente baixa foi determinada durante diversas atividades diárias desenvolvidas pelos indígenas. Considerando-se a incidência de câncer em diferentes cidades brasileiras, a probabilidade de ocorrência ao acaso deste agrupamento de casos foi considerada remota (p<0,03, distribuição de Poisson). Níveis elevados de p,p'-DDT (mediana variando entre 26 e 58 ppb) foram observados nas amostras estudadas. A exposição contínua aos campos eletromagnéticos de freqüência extremamente baixa, a qual atingiu 95 mG abaixo das linhas de transmissão, foi observada em diversas oportunidades durante atividades diárias desenvolvidas pelos indígenas. Estudos observacionais futuros deveriam analisar a interação da exposição aos campos eletromagnéticos de freqüência extremamente baixa (50-60 Hz) subseqüente à exposição a agentes de iniciação tumoral no desenvolvimento de neoplasias.

A case study was carried out to explore the occurrence of a cancer cluster in 1992 among young indian adults living in an Amazonian village near two 500 kV power transmission lines that began operating a decade ago. Current blood levels of DDT and organophosphorus pesticides and metal levels in hair samples were measured. Extremely low magnetic field exposure was determined during current daily activities carried out by the Indian villagers. Taking into account the cancer incidence rates in different Brazilian cities, the probability of the occurrence of this cluster by chance was considered remote (p< 0.003, Poisson distribution). High blood levels of p,p'-DDT (median levels ranging from 26 to 58 ppb) were observed. As a whole, this community showed a pattern of low exposure to organophosphorus pesticides, and high recent exposure was only observed in a few blood samples. Continuous exposure to extremely low electromagnetic fields originated in the power transmission lines (which reached 95.0 mG under the lines) was observed on several opportunities during daily activities carried out by Indian villagers. Further observational studies should evaluate the interaction between exposure to extremely low electromagnetic fields and prior exposure to tumor initiators in cancer development.

Realizou-se a análise exploratória de um conjunto de atestados de óbito de eletricitários do Estado de São Paulo (Brasil), através da Razão de Mortalidade Proporcional (PMR) e da Razão de Mortalidade Proporcional por Câncer (PCMR). Foi observado um discreto excesso de mortalidade por todas as localizações de câncer (PMR 1,11; IC 95% 0,91-1,35), estatisticamente não significativo. Encontrou-se elevação da PCMR, estatisticamente significativa, para câncer de laringe (PCMR 2,04; IC 95% 1,05-4,20). Um excesso de óbitos, embora sem significação estatística, foi observado para cavidade oral/faringe, próstata, bexiga, cérebro e doença de Hodgkin. A análise por categorias de exposição estimada a campos magnéticos mostrou PCMRs persistentemente elevadas para cancêr de bexiga (PCMR 4,17; IC 95% 1,35-9,72), cérebro (PCMR 3,77; IC 95% 1,02-9,65) e doença de Hodgkin (PCMR 5,55; IC 95% 1,14-16,21), no grupo com exposição provavelmente alta. Uma comparação com a mortalidade por câncer, de um grupo de trabalhadores petroquímicos, mostrou mortalidade elevada por neoplasma de laringe (PCMR 3,51; IC 95% 1,75-6,28) e bexiga (PCMR 7,53; IC 95% 3,02-15,51). Para tumores de cérebro, observou-se PCMR de 0,74 (IC 95% 0,27-1,61).

A number of epidemiologic studies have observed an association between exposure to 50-60 Hz electromagnetic fields and the development of specific types of cancer. In Brazil, a preliminary report from a study of electricity facility workers in Rio de Janeiro (RJ) has mentioned relatively similar results. An exploratory analysis of death certificates obtained from a sample of electricity workers in S. Paulo was made. Data was analysed by using the Proportional Mortality Ratio (PMR) and the Proportional Cancer Mortality Ratio (PCMR). A slightly elevated all-sites cancer mortality was observed among these workers (PMR 1.11; 95% CI 0.91-1.35). Site specific analysis has shown a statistically significant higher mortality of laryngeal cancer (PCMR 2.04; 95% CI 1.05-4.20). An excess of deaths was also seen for cancers of the buccal cavity/pharynx, prostate, bladder, brain and Hodgkin's disease, although the results lacked statistical significance. When analysed by categories of estimated exposure to magnetic fields, an excess of deaths from bladder cancer (PCMR 4.17; 95% CI 1.35-9.72), neoplasms of the brain (PCMR 7.7; 95% CI 1.02-9.65) and Hodgkin's disease (PCMR 5.55; 95% CI 1.14-16.21) was observed in the group with probably higher exposure to EMF. A comparison of cancer mortality between these workers and petrochemical employees has shown a higher PCMR for larynx tumours (PCMR 3.51; 95% CI 3.02-15.51) and bladder cancer (PCMR 7.53; 95% CI 3.02-15.51). For brain tumours, however, a PCMR of 0,74 (95% CI 0.27-1.61) was noted. Although restrictions related to sample size in the study and the lack of information about known confounders must be considered, the results of this study do not fully disagree with others previously mentioned in the literature.

Realizou-se a análise exploratória de um conjunto de atestados de óbito de eletricitários do Estado de São Paulo (Brasil), através da Razão de Mortalidade Proporcional (PMR) e da Razão de Mortalidade Proporcional por Câncer (PCMR). Foi observado um discreto excesso de mortalidade por todas as localizações de câncer (PMR 1,11; IC 95% 0,91-1,35), estatisticamente não significativo. Encontrou-se elevação da PCMR, estatisticamente significativa, para câncer de laringe (PCMR 2,04; IC 95% 1,05-4,20). Um excesso de óbitos, embora sem significação estatística, foi observado para cavidade oral/faringe, próstata, bexiga, cérebro e doença de Hodgkin. A análise por categorias de exposição estimada a campos magnéticos mostrou PCMRs persistentemente elevadas para cancêr de bexiga (PCMR 4,17; IC 95% 1,35-9,72), cérebro (PCMR 3,77; IC 95% 1,02-9,65) e doença de Hodgkin (PCMR 5,55; IC 95% 1,14-16,21), no grupo com exposição provavelmente alta. Uma comparação com a mortalidade por câncer, de um grupo de trabalhadores petroquímicos, mostrou mortalidade elevada por neoplasma de laringe (PCMR 3,51; IC 95% 1,75-6,28) e bexiga (PCMR 7,53; IC 95% 3,02-15,51). Para tumores de cérebro, observou-se PCMR de 0,74 (IC 95% 0,27-1,61).

A number of epidemiologic studies have observed an association between exposure to 50-60 Hz electromagnetic fields and the development of specific types of cancer. In Brazil, a preliminary report from a study of electricity facility workers in Rio de Janeiro (RJ) has mentioned relatively similar results. An exploratory analysis of death certificates obtained from a sample of electricity workers in S. Paulo was made. Data was analysed by using the Proportional Mortality Ratio (PMR) and the Proportional Cancer Mortality Ratio (PCMR). A slightly elevated all-sites cancer mortality was observed among these workers (PMR 1.11; 95% CI 0.91-1.35). Site specific analysis has shown a statistically significant higher mortality of laryngeal cancer (PCMR 2.04; 95% CI 1.05-4.20). An excess of deaths was also seen for cancers of the buccal cavity/pharynx, prostate, bladder, brain and Hodgkin's disease, although the results lacked statistical significance. When analysed by categories of estimated exposure to magnetic fields, an excess of deaths from bladder cancer (PCMR 4.17; 95% CI 1.35-9.72), neoplasms of the brain (PCMR 7.7; 95% CI 1.02-9.65) and Hodgkin's disease (PCMR 5.55; 95% CI 1.14-16.21) was observed in the group with probably higher exposure to EMF. A comparison of cancer mortality between these workers and petrochemical employees has shown a higher PCMR for larynx tumours (PCMR 3.51; 95% CI 3.02-15.51) and bladder cancer (PCMR 7.53; 95% CI 3.02-15.51). For brain tumours, however, a PCMR of 0,74 (95% CI 0.27-1.61) was noted. Although restrictions related to sample size in the study and the lack of information about known confounders must be considered, the results of this study do not fully disagree with others previously mentioned in the literature.