Nasopharyngeal carcinoma is a disease with a remarkable racial and geographical distribution. In most parts of the world it is a rare condition and in only a handful of places does this low risk profile alter. These include the Southern Chinese, Eskimos and other Arctic natives, inhabitants of South-East Asia and also the populations of North Africa and Kuwait.
Thyroid cancer is a relatively rare cancer (5 new cases/y/10(5) inhabitants). An excess of thyroid carcinoma has been found in some but not in all goiter endemic areas. Follicular and anaplastic carcinomas have been found particularly frequent in regions of goitre endemia. A significant increase of thyroid carcinoma has also been found in iodine sufficient areas (Norway, Iceland, Hawaii). In several surveys a positive correlation has been found between parity and incidence of differentiated thyroid carcinoma. Natural goitrogens and chemotherapeutic agents have been proved to induce hyperplasia but their role in carcinogenesis of exposed populations is not yet definitely ascertained. Exposure to external radiation is carcinogenic for the thyroid both in human and in experimental animals. Patients treated for hyperthyroidism or thyroid cancer or given diagnostic doses of 131-I (0.5 Gy/test) indicate that under these conditions 131-I is not carcinogenic. Findings on population exposed to radioactive fallout showed an increased incidence of thyroid carcinomas compared to unexposed populations. After the Chernobyl accident (1986) particular attention was given to calculate the risk of thyroid cancer caused by the fallout of 131-I. Up to now a considerable increase of thyroid carcinoma has been reported in children of a region near Chernobyl (Belarus).
Although the incidence of testicular cancer is increasing, substantial differences in incidence between countries and populations exist. These differences cannot be explained solely by genetic differences, but environmental exposures, particularly early exposures, have been implicated in the etiology of testicular cancer. To assess whether early exposures contribute to the incidence of testicular cancer, we identified 93 172 Finnish men who immigrated to Sweden between 1969 and 1996 and followed them for the occurrence of testicular cancer. The risk of testicular cancer was lower for Finnish immigrants to Sweden than for the Swedish general population (standardized incidence ratio [SIR] = 0.34, 95% confidence interval [CI] = 0.21 to 0.53). The reduced risk was associated with both seminomas and non-seminomas. Neither age at immigration nor duration of stay in Sweden had any impact on the reduced risk. Although the type of environmental exposures remains unknown, the results strongly indicate that early exposures are major determinants for testicular cancer.
Ethnicity is associated with genetic, environmental, lifestyle and social constructs. Difficult to define using a single variable, but strongly predictive of health outcomes and useful for planning healthcare services, it is often lacking in administrative databases, necessitating the use of a surrogate measure. A potential surrogate for ethnicity is birthplace. Our aim was to measure the agreement between birthplace and ethnicity among six major ethic groups as recorded at the population-based mammography service for British Columbia, Canada (BC).
We used records from the most-recent visits of women attending the Screening Mammography Program of British Columbia to cross-tabulate women's birthplaces and self-reported ethnicities, and separately considered results for the time periods 1990-1999 and 2000-2006. In general, we combined countries according to the system adopted by the United Nations, and defined ethnic groups that correspond to the nation groups. The analysis considered birthplaces and corresponding ethnicities for South Asia, East/Southeast Asia, North Europe, South Europe, East Europe, West Europe and all other nations combined. We used the kappa statistic to measure the concordance between self-reported ethnicity and birthplace.
Except for the 'Other' category, the most-common birthplace was East/Southeast Asia and the most-common ethnicity was East/Southeast Asian. The agreement between birthplace and self-reported ethnicity was poor overall, as evidenced by kappa scores of 0.22 in both 1990-1999 and 2000-2006. There was substantial agreement between ethnicity and birthplace for South Asians, excellent agreement for East/Southeast Asians, but poor agreement for Europeans.
Birthplace can be used as a surrogate for ethnicity amongst people with South Asian and East/Southeast Asian ethnicity in BC.
Members of American Indian and Alaska Native (AI/AN) tribes have a unique political status in the United States in terms of citizenship, and that political status determines eligibility for certain unique healthcare services. The AI/AN population has a legal right to healthcare services based on treaties, court decisions, acts of Congress, Executive Orders, and other legal bases. Although the AI/AN population has a right to healthcare services, the Indian Health Service (the federal agency responsible for providing healthcare to AI/ANs) is severely underfunded, limiting access to services (including cancer care). In order to overcome distinct cancer health disparities, policy changes will be needed. This paper reviews the historical pattern of AI/AN healthcare and the challenges of the complex care needed from prevention through end-of-life care for cancer.
Recently, a T-to-A transversion creating an 8-base mononucleotide tract in the APC gene, resulting in substitution of lysine for isoleucine at codon 1307 (I1307K), was found in a subset of Ashkenazi Jews. This sequence variant was most frequent in colorectal cancer patients with a positive family history of colorectal cancer. To determine whether the I1307K variant plays a role in colorectal or breast cancer predisposition in the Norwegian population, we have analyzed blood samples from 210 colorectal cancer patients and 183 breast cancer patients by PCR and direct sequencing. Thirty-seven of the colorectal cancer patients had a positive family history of cancer. Among the breast cancer patients, 24 had a family history of colorectal cancer and 75 a family history of breast and/or ovarian cancer. Only one colorectal cancer patient who belonged to a Jewish family was found to carry the A variant. Our data show that the I1307K variant is rare in the Norwegian population and should not be viewed as a candidate for susceptibility testing for colorectal cancer.
Associations between socioeconomic status (SES) and the incidence of cancer have been reported previously in the U.S. Canada has more comprehensive health care and social programs than the U.S. The purpose of this study was to compare the strength of associations between SES and cancer incidence in Canada and the U.S.
The regions studied were the Canadian province of Ontario and the areas of the U.S. covered by the Surveillance, Epidemiology, and End Results (SEER) program. The populations at risk were defined using the 1991 Canadian Census and the 1990 U.S. Census. The populations of Ontario and of the SEER areas of the U.S. were each divided into deciles on the basis of median household income. Population-based cancer registries were used to identify incident cases. Age-standardized incidence rates for all major groups of malignant diseases were calculated for each SES decile in Ontario and in the U.S. Income-associated incidence gradients observed in Ontario and the U.S. were compared.
The incidence of most types of cancer was similar in Ontario and the U.S. In both countries, there were moderately strong, inverse associations between income level and the incidence of carcinomas of the cervix, the head and neck region, the lung, and the gastrointestinal tract. In both Ontario and the U.S., several of these diseases were twice as common in the bottom income decile than they were in the top decile. In contrast, carcinoma of the female breast and carcinoma of the prostate were more common among higher income communities in both countries, but the observed associations were weaker in Ontario.
Despite Canada's universal health insurance and more comprehensive social security system, the association between lower socioeconomic status and the incidence of many common cancers is just as strong in Ontario as it is in the U.S. The mechanisms responsible for these associations require further investigation.
The MDM2 promoter region contains several polymorphisms, some of which have been associated with MDM2 expression, cancer risk and age at cancer onset. del1518 (rs3730485) is an indel polymorphism residing in the MDM2 promoter P1 and is in almost complete linkage disequilibrium with the MDM2 promoter P2 polymorphism SNP309T>G (rs2279744). Cancer risk assessments of del1518 have previously been conducted in relatively small Chinese populations only. In this study we assessed the genotype distribution of del1518 among healthy Caucasians, African Americans and Chinese, and we estimated the Odds Ratios (OR) for incident cancer of the breast, colon, lung and prostate (n=7,081) as compared to controls (n=3,749) in a large Caucasian (Norwegian) cohort.We found the genotypes of the del1518 to vary significantly between healthy Caucasians, African-Americans and Chinese (p
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A bibliometric analysis was employed to objectively assess scientific studies published between 1966 and 1993 which have described cancer among American Indians and Alaska Natives. Searches of the MEDLINE (1966-1993) and CANCERLIT data bases (1983-1994) were used to identify relevant publications. In addition to examining publication sources and quantitative temporal trends, further bibliometric analyses were completed by considering a subset of papers published between 1982 and 1992. A total of 128 studies of cancer among American Indians and Alaska Natives were published between 1966 and 1993; 62 of these articles (48%) appeared between 1988 and 1993. Nine journals accounted for 53% of the total publications. The subset of 68 papers published between 1982 and 1992 were cited a total of 388 times in 136 different journals; the median number of citations was 2. Results demonstrate a limited number of published papers on cancer among American Indians and Alaska Natives. It is hoped that this paper will increase the awareness of cancer as an important health problem among American Indian and Alaska Natives and thereby serve to stimulate additional cancer-related research activities involving these groups.
We have screened index cases from 25 Russian breast/ovarian cancer families for germ-line mutations in all coding exons of the BRCA1 and BRCA2 genes, using multiplex heteroduplex analysis. In addition we tested 22 patients with breast cancer diagnosed before age 40 without family history and 6 patients with bilateral breast cancer. The frequency of families with germline mutations in BRCA was 16% (4/25). One BRCA1 mutation, 5382insC, was found in three families. The results of present study, and those of a separate study of 19 breast-ovarian cancer families, suggest that BRCA1 5382insC is a founder mutation in the Russian population. Three BRCA2 mutations were found in patients with breast cancer without family history: two in young patients and one in patients with bilateral breast cancer. Four novel BRCA2 mutations were identified: three frameshift (695insT, 1528del4, 9318del4) and one nonsense (S1099X).