Systematic population-based assessment of cancer risk in first-degree relatives of cancer probands

Association of brain tumours with other neoplasms in families

We used the nationwide Swedish Family-Cancer Database to analyse the association of histology-specific brain tumours with other cancers in family members. Among 0-68-year-old offspring, 9414 patients with brain tumours were identified from 1961 to 2000, of whom, 3387 parents were diagnosed with any primary neoplasm. Astrocytoma, meningioma and neurinoma were the main histological types. Increased standardised incidence ratios (SIRs) were found for brain tumours in association with cancers at sites that are known features in recognised syndromes, such as haemangioblastoma and renal cancer in von Hippel-Lindau disease. In addition, an association between astrocytoma and melanoma was recognised. Among as yet unknown clustering, neurinoma was associated with testicular cancer and myeloma; meningioma was associated with cervical cancer; astrocytoma was associated with prostate cancer; ependymoma was associated with breast cancer. Although some of these may feature a true tumour cluster, they need to be confirmed in another setting.

Pathophysiological Dynamics of Human Ovarian Surface Epithelial Cells in Epithelial Ovarian Carcinogenesis

Epithelial ovarian cancer is responsible for almost half of all the deaths from female genital tract tumors. Major impediments to the clinical treatment of this disease are the relatively asymptomatic progression and a lack of knowledge regarding defined precursor or malignant lesions. Most epithelial ovarian cancers are thought to arise from the transformation of ovarian surface epithelial cells, a single continuous layer of flat-to-cuboidal mesothelial cells surrounding the ovary. To improve our understanding of the pathogenesis of epithelial ovarian cancer, it is necessary to study the biological characteristics of normal ovarian surface epithelial cells. However, this approach has been hampered by the inability to purify and culture such human cells. During the past decade, procedures to isolate and culture human ovarian surface epithelial cells have been developed, and, subsequently, using viral oncogenes, several immortalized cells have been established. This new experimental system is being employed to improve our understanding of the genetic changes leading to the initiation of epithelial ovarian cancer and to identify events in the cancer's development. This review mainly describes the biological dynamics of ovarian surface epithelial cells in the pathogenesis of epithelial ovarian cancer, focusing on humans and excluding small animal models.

Familial association of specific histologic types of ovarian malignancy with other malignancies

BACKGROUND

Population-based data on the familial association of specific histologic types of ovarian malignancy with other malignancies are limited. Such data may help to elucidate etiologic differences among histologic types of ovarian malignancy.

METHODS

The nationwide Swedish Family-Cancer Database, which includes 10.3 million individuals and 20,974 ovarian carcinomas, was used to calculate standardized incidence ratios and 95% confidence intervals for age- and histology-specific ovarian malignancies in women whose parents or siblings were affected with malignancies at the most common disease sites.

RESULTS

Ovarian malignancy was found to be associated with ovarian, laryngeal, breast, endometrial, liver, and colon carcinoma, as well as myeloma; epithelial ovarian malignancy was found to be associated with ovarian, endometrial, and skin malignancies and with melanoma and myeloma; papillary serous cystadenocarcinoma was found to be associated with ovarian and skin malignancies and with myeloma; and endometrioid carcinoma was found to be associated with endometrial, ovarian, and prostate malignancies and with melanoma. For younger women (ages 40-45 years) whose mothers were affected with endometrial malignancies, the risk of developing endometrioid carcinoma was slightly greater than the risk of developing papillary serous cystadenocarcinoma.

CONCLUSIONS

Specific types of ovarian malignancy may be associated with specific familial disease sites, with such associations depending on age at diagnosis; the strength of the observed associations varied according to histology. Associations were found between endometrioid carcinoma and endometrial malignancy and between serous carcinoma and Hodgkin disease.

Site-specific familial aggregation of prostate cancer

Over the last decade, epidemiologic evidence has accumulated in favor of a significant but heterogeneous hereditary component in prostate cancer (PC) susceptibility. In order to map and clone PC susceptibility genes, stratification of PC families into genetically homogeneous groups appears to be a key issue. Subset definition based on age at diagnosis, presumed mode of inheritance, number of affecteds per family and coaggregation of PC with other cancers has already proven successful in some studies. Previously, the finding of the coaggregation of malignancies of the central nervous system within PC families helped to link a prostate-brain cancer susceptibility gene (CAPB) to chromosome 1p36. In this study, we evaluate the risk of PC and malignancies at other sites among first-degree relatives of a large population-based group of Dutch PC patients. A population-based family case-control study was initiated that included Caucasian PC patients newly diagnosed between July 1996 and December 1999. Information on 12,575 first-degree relatives of 704 PC patients and 1,371 controls was collected through postal questionnaires and telephone interviews. All reported PC in first-degree relatives was verified through medical records. In our population, PC has a strong familial component that is reflected by a 2.9-fold increased risk (95% CI = 2.2-3.9) of PC for first-degree relatives of PC patients. This familial risk was somewhat higher among brothers (hazard ratio = 3.9; 95% CI = 2.4-6.4) compared to fathers (hazard ratio = 2.5; 95% CI = 1.7-3.6). Cancers at other sites did not coaggregate with PC. Our data suggest that familial PC, at least in this Western European population, is site-specific, not part of an inherited cancer syndrome.

Genetic epidemiology of cancer: From families to heritable genes

A reliable determination of familial risks for cancer is important for clinical counseling, prevention and understanding cancer etiology. Family-based gene identification efforts may be targeted if the risks are well characterized and the mode of inheritance is identified. Medically verified data on familial risks have not been available for all types of cancer but they have become available through the use of the nationwide Swedish Family-Cancer Database, which includes all Swedes born in 1932 and later with their parents, totaling over 10 million individuals. Over 150 publications have emanated from this source. The familial risks of cancer have been characterized for all main cancers and the contribution of environmental and heritable effects to the familial aggregation has been assessed. Furthermore, the mode of inheritance has been deduced by comparing risks from parental and sibling probands. Examples are shown on familial clustering of cancers, for which heritable susceptibility genes are yet unknown, such as squamous cell carcinoma of the skin, intestinal carcinoids, thyroid papillary tumors, brain astrocytomas and pituitary adenomas. Some common cancers, such as lung and kidney cancers, appear to show an early-onset recessive component because familial risks among siblings are much higher than those in families where parents are probands. Many of the cancer sites showing high familial risks lack guidelines for clinical counseling or action level. In conclusion, we recommend that any future gene identification efforts, either using linkage or association designs, devise their strategies based on data from family studies. Clinical genetic counseling would benefit from reviewing established familial risks on all main types of cancer.

The effect of disease penetrance, family size, and age of onset on family history with application to setting eligibility criteria for genetic testing

The concept of family history of disease has been used as a surrogate for genetic susceptibility in many epidemiological studies and has also been important as a criterion for selecting individuals for genetic testing. However, little is known about the precise interplay between the true genetic model (genotype-specific penetrances, age of onset distribution), life expectancy, and reproductive patterns in determining the level of family history. In order to address these questions, we performed a simulation study to address these relationships. Factors examined were the age-, sex-, and genotype-specific penetrance of the disease and the distribution of the number of offspring per family. When considering the average number of affected individuals among first-degree relatives of mutation positive probands, penetrance-related factors accounted for 64% of the variance in the average number of affected first-degree relatives, and 58% of the variance in the number of affected first- or second-degree relatives. In general, the average proportion of mutation-positive probands with at least one affected first-degree relative was low, especially for a sex-limited disease, ranging between 20% and 46%, depending on the lifetime penetrance in mutation carriers. Lack of family history among first-degree relatives of mutation positive probands is not necessarily unexpected even for loci conferring relatively high lifetime risk. In selecting probands for genetic testing, we found that under a wide variety of conditions, criteria based on the number of affected among first- and second-degree relatives were superior to those based on first-degree family history alone.

Genetic susceptibility to prostate cancer: a review

A genetic component in prostate cancer has been recognized since decades. Through numerous epidemiological and molecular biological studies, much evidence has accumulated in favor of a significant but heterogeneous hereditary component in prostate cancer (PCa) susceptibility. Since the mapping of a high-penetrant PCa susceptibility locus at 1q24-25, much attention has been paid to the identification of PCa susceptibility genes. So far, seven loci have been mapped, and at three of these loci, genes have been cloned and mutations identified. Yet their role in hereditary and sporadic disease is still under debate and probably very modest. Although research on hereditary prostate cancer has improved our knowledge of the genetic etiology of the disease, still a lot of questions remain unanswered. Here, we aim to review the genetic epidemiological and molecular biological research in the field of hereditary prostate cancer and the problems that are encountered with this research.

Relative risk of prostate cancer for men with affected relatives: systematic review and meta-analysis

An increased risk of prostate cancer associated with a family history of prostate cancer has been documented in multiple published reports. Risk has been shown to vary by degree of relationship and age of onset of disease in the affected relative. Several studies, using various designs, have estimated the relative risk (RR) for these associations. The purpose of our study was to identify and summarize published reports on the relationship between risk of prostate cancer and family history, which is defined as having a father, brother, any first- or second-degree relative or other relative affected with prostate cancer. A Medline and manual search from 1982 to 2000 identified 24 studies that reported RR and confidence intervals (CI) and satisfied inclusion criteria. Pooled RR estimates based upon a weighted average model were as follows: any affected family member RR = 1.93, CI 1.65-2.26; affected first-degree relative RR = 2.22, CI 2.06-2.40; affected second-degree relative RR = 1.88, CI 1.54-2.30; father with prostate cancer RR = 2.12, CI 1.82-2.51; and brother with prostate cancer RR = 2.87, CI 2.21-3.73). Statistical comparison of pooled data demonstrated that the RR is significantly higher for affected brother than for affected father (p < 0.03). A sensitivity analysis demonstrated that these results are robust with respect to population bias. This meta-analysis confirms that risk of prostate cancer is associated with family history of disease and improves the quantification of this risk.

Where are the prostate cancer genes?--A summary of eight genome wide searches

BACKGROUND

There is strong evidence for genetic susceptibility to prostate cancer, but most of the genes underlying this susceptibility remain to be identified.

METHODS

We reviewed the results of eight genome-wide linkage searches based on 1,293 families with multiple cases of prostate cancer.

RESULTS

Across these studies, 11 linkage peaks with LOD scores in excess of 2 were identified. However, no chromosomal region was reported as significant at this level by more than one study and only one corresponded to a peak previously suggested by another group.

CONCLUSIONS

These results indicate that prostate cancer is genetically complex, and that combined analyses of large family sets will be required to evaluate reliably the linkage evidence.

Genomic scan of 254 hereditary prostate cancer families

Hereditary prostate cancer (HPC) is a genetically heterogeneous disease, complicating efforts to map and clone susceptibility loci. We have used stratification of a large dataset of 254 HPC families in an effort to improve power to detect HPC loci and to understand what types of family features may improve locus identification. The strongest result is that of a dominant locus at 6p22.3 (heterogeneity LOD (HLOD) = 2.51), the evidence for which is increased by consideration of the age of PC onset (HLOD = 3.43 in 214 families with median age-of-onset 56-72 years) and co-occurrence of primary brain cancer (HLOD = 2.34 in 21 families) in the families. Additional regions for which we observe modest evidence for linkage include chromosome 7q and 17p. Only weak evidence of several previously implicated HPC regions is detected. These analyses support the existence of multiple HPC loci, whose presence may be best identified by analyses of large, including pooled, datasets which consider locus heterogeneity.

Results of a genome-wide linkage analysis in prostate cancer families ascertained through the ACTANE consortium

BACKGROUND

The aggregation of prostate cancer within families suggests a major inherited component to the disease. Genetic linkage studies have identified several chromosomal regions that may contain prostate cancer susceptibility loci, but none has been definitively implicated.

METHODS

We performed a genome-wide linkage search based on 64 families, 63 with at least 3 cases of prostate cancer, ascertained in five countries. The majority of cases from these centers presented with clinically detected disease. Four hundred and one polymorphic markers were typed in 268 individuals. Multipoint heterogeneity analysis was conducted under three models of susceptibility; non-parametric analyses were also performed.

RESULTS

Some weak evidence of linkage, under at least one of the genetic models, was observed to markers on chromosomes 2 (heterogeneity LOD (HLOD) = 1.15, P = 0.021), 3 (HLOD = 1.25, P = 0.016), 4 (HLOD = 1.28, P = 0.015), 5 (HLOD = 1.20, P = 0.019), 6 (HLOD = 1.41, P = 0.011), and 11 (HLOD = 1.24, P = 0.018), and in two regions on chromosome 18 (HLOD = 1.40, P = 0.011 and HLOD = 1.34, P = 0.013). There were no HLOD scores greater than 1.5 under any model, and no locus would be predicted to explain more than half of the genetic effect. No evidence in favor of linkage to previously suggested regions on chromosomes 1, 8, 17, 20, or X was found.

CONCLUSIONS

Genetic susceptibility to prostate cancer is likely to be controlled by many loci, with no single gene explaining a large fraction of the familial risk. Pooling of results from all available genome scans is likely to be required to obtain definitive linkage results.

Genome linkage screen for prostate cancer susceptibility loci: results from the Mayo Clinic Familial Prostate Cancer Study

Prostate cancer is one of the most common cancers among men and has long been recognized to occur in familial clusters. Brothers and sons of affected men have a twofold to threefold increased risk of developing prostate cancer. However, identification of genetic susceptibility loci for prostate cancer has been extremely difficult. Several putative loci identified by genetic linkage have been reported to exist on chromosomes 1 (HPC1, PCAP, and CAPB), X (HPCX), 17 (HPC2), and 20 (HPC20), with genes RNASEL (HPC1) and ELAC2 (HPC2) tentatively defined. In this study, we report our genome linkage scan in 160 prostate cancer families, using the ABI Prism Linkage Mapping Set Version 2 with 402 microsatellite markers. The most significant linkage was found for chromosome 20, with a recessive model heterogeneity LOD score (HLOD) of 4.77, and a model-free LOD score (LOD - ZLR) of 3.46 for the entire group of pedigrees. Linkage for chromosome 20 was most prominent among families with a late age of diagnosis (average age at diagnosis >/= 66 years; maximum LOD - ZLR = 2.82), with <5 affected family members (LOD - ZLR = 3.02), with presence of hereditary prostate cancer (LOD - ZLR = 2.81), or with no male-to-male transmission of disease (LOD - ZLR = 3.84). No other chromosome showed significant evidence for linkage. However, chromosomes 6 and X showed suggestive results, with maximum LOD - ZLR values of 1.38 and 1.36, respectively. Subset analyses suggest additional chromosomal regions worth further follow-up.

Double primary cancers of the breast and thyroid in women: molecular analysis and genetic implications

Multiple primary cancers are characteristic of hereditary cancer syndromes. A familial association between breast and thyroid cancer has been suggested, but a genetic basis for this association has not yet been established. To determine the extent to which double primary cancers of the breast and thyroid are due to common hereditary factors, we conducted a registry- and hospital-based study in Ontario and Quebec. We obtained family histories of 74 women diagnosed with both cancer of the breast and thyroid before 70 years of age. Cancer histories were obtained for the 533 first- degree relatives of these women. The observed cancer rate in the relatives was compared with the expected number, based on age- standardized Canadian cancer incidence rates, and relative risks were estimated. A total of 87 cancers were observed in the relatives, compared to 93.7 expected cancers, giving a relative risk of 0.9 (95% confidence interval (CI): 0.7-1.1). The risk for breast cancer was 1.1 (95% CI: 0.6-1.7) and the risk for thyroid cancer was 0.7 (95% CI: 0-3.8). Blood samples were collected on 53 patients for mutational analysis of the BRCA1, BRCA2, and PTEN genes. One woman was found to be a carrier of a BRCA1 mutation (exon 11 3227delT). Our findings do not support the hypothesis that a significant proportion of double primary cancers of the breast and thyroid are due to hereditary factors.

Population-based study of familial medullary thyroid cancer

BACKGROUND

We wanted to carry out a population-based study on medullary thyroid cancer (MTC) in order to quantify familial risks.

METHODS

MTC was studied in the Swedish Family-Cancer Database, updated in 1999 to cover individuals and offspring, born after 1934 with their biological parents, totaling 9.6 million persons. Cancer data were obtained from the Swedish Cancer Registry from year 1958 to 1996 and included 2,435 thyroid cancers among offspring.

RESULTS

65 offspring were identified with MTC, which was coded as a separate entity since 1985. 62% had neither affected parent nor sib. Most familial cases were diagnosed at ages 15 to 24 and sporadic cases 25 years later. The familial SIRs of MTC were 3,080 and 3,650 when either a parent or a sib had MTC; when both had MTC the SIR was 35,800. All the familial risks were highest in young age groups, 0-9 years. MEN 2 or MEN 2-like families were considered when one family member had a TC and an adrenal pheochromocytoma. SIR of MTC in offspring was 61,000 when a parent had a MEN 2-like cancer and a sib had MTC.

CONCLUSIONS

We described familial and sporadic MTC in a population-based database. The familial risks of MTC may be the highest ever reported in population based studies.

Evaluation of familial clustering of breast and prostate cancer in the Minnesota Breast Cancer Family Study

Few studies examining familial clustering of breast and prostate cancer (PC) have focused on a clearly defined high-risk population with epidemiologic risk factors. We conducted a cohort study of prostate cancer among a subset of 426 families ascertained through female breast cancer probands. Three groups of males were included: 804 relatives in 60 families with four or more breast or ovarian cancers, 536 marry-ins in these high-risk families, and 484 relatives in 81 families where only the proband had breast cancer. A total of 118 prostate cancers were reported. The rate of prostate cancer among blood relatives in high-risk families was significantly lower than among marry-ins (RR = 0.6, 95% C.I.: 0.4-0.9). The rate of prostate cancer among blood relatives in low-risk families was not significantly different from the rate among marry-ins (RR = 0.8, 95% C.I.: 0.5-1.2). These results provide little evidence that male relatives in high-risk breast cancer families are at increased risk of prostate cancer.

Causation of chronic lymphocytic leukemia--insights from familial disease

In Western countries B-cell chronic lymphocytic leukemia (CLL) is the most common form of leukemia. Evidence from epidemiological studies and family studies strongly supports the notion that a subset of CLL involves inherited susceptibility. Identification of genes predisposing to CLL should be useful for diagnosis and treatment, as well as serving as a model for B-cell tumorigenesis in general. Here, we review the current status of knowledge about inherited susceptibility to CLL.

Familial relative risk of colorectal cancer: a population-based study

This study aimed to assess the familial relative risk for colorectal cancer (CRC) and its variation according to age and gender. A population-based family study was carried out in France, from 1993 to 1998, including 761 families. Familial CRC risks were estimated from a cohort analysis of the relatives. No obvious decrease in CRC risk was found with increasing age, except when either the proband, or the relative, were in the youngest age class. The effect of the relatives' and probands' ages on the CRC risk differed according to their gender. The cumulative risk of CRC increased at an earlier age in male relatives of probands younger than 60 years of age, than in female relatives. This result suggests that mechanisms specific to females, possibly interacting with genetic factors, explain the difference in the cumulative risks between families with male and female probands.

Malignant tumors in first-degree relatives of cancer patients aged 0-25 years (province of Trieste, Italy)

To determine whether the occurrence of first and second primary malignancies in first-degree relatives of cancer patients aged 0-25 years (probands) differed from that in the general population, a cohort study was carried out on 860 relatives of 265 probands living in the province of Trieste, Italy. During the follow-up period (median duration = 28 years, 25th-75th percentile = 20-34), the relatives developed 103 first primary cancers vs. 88.9 expected for a standardized incidence ratio (SIR) of 1.2 (p = 0.2). Significantly elevated risks were found for melanoma in the parents of probands aged 15-25 years with melanoma (SIR = 15.0, p = 0.002), for hemolymphatic malignancies in the fathers of probands aged 0-14 years with brain tumors (SIR = 13.3, p = 0.0005) and for hemolymphatic cancers in relatives as a whole of probands aged 15-25 years with lymphomas (SIR = 4.5, p = 0.01). During the follow-up period, 7 relatives with a first primary cancer had a subsequent malignancy vs. 4.2 expected for an SIR of 1.7 (p = 0.3). Our results indicate that young cancer patients per se should not to be considered as a factor that usually increases the risk of developing malignant tumors among their first-degree relatives, except when a known cancer family syndrome or predisposition is recognized.

Cancer incidence in relatives of a population-based set of cases of early-onset breast cancer with a known BRCA1 and BRCA2 mutation status

BACKGROUND

Relatives of breast cancer cases have an increased risk of the disease. The risk increases with increasing numbers and decreasing age of onset of affected relatives. In families with a BRCA1 or a BRCA2 mutation, individual carrier status predicts the risk of breast cancer. In relatives of cases where both BRCA1 and BRCA2 mutations are excluded, the risk remains undetermined.

METHODS

Standardized incidence ratios (SIRs) and cumulative cancer incidences were calculated for relatives of a population-based set of early-onset breast cancer index cases (younger than age 41 years) with a defined BRCA mutation status (n = 203).

RESULTS

In first-degree relatives (FDRs) of mutation-negative cases, breast cancer incidences (SIR = 2.3), prostate cancer incidences (SIR = 1.7), cervix cancer incidences (SIR = 3.3) and nonmelanoma skin cancer incidences (SIR = 2.8) were increased. The risks of breast cancer, prostate cancer and nonmelanoma skin cancer were further increased in FDRs of breast cancer cases younger than 36 years of age. In high-risk individuals with at least one relative with breast cancer apart from the index case, but no BRCA mutation in the family, breast cancer incidence was increased (SIR = 5.3); again the prostate cancer incidence was elevated (SIR = 2.5). The cumulative incidence of breast cancer at ages 50 and 70 years for FDRs of index cases without a BRCA mutation was 3.6% and 12.8%, respectively. Similarly, the cumulative incidence of breast cancer for high-risk women was 6.3% and 21.1% at ages 50 and 70 years, and that for FDRs of BRCA mutation carriers was 17.2% and 27.7% at the same ages.

CONCLUSION

The incidence of breast cancer is increased for FDRs of women with early-onset breast cancer irrespective of the BRCA status in the family. Risk increases with decreasing age and with increasing number of affected relatives. The incidences of prostate cancer, cervix cancer and nonmelanoma skin cancer are elevated for FDRs of early-onset breast cancer cases without a BRCA mutation, indicating a possible association between these cancers and early-onset breast cancer.

Exposure to animals and selected risk factors among Canadian farm residents with Hodgkin's disease, multiple myeloma, or soft tissue sarcoma

Exposures to farm animals has been associated with certain rare cancers. Simultaneously, using the same methodology and control group, we conducted a six-province incident, population-based study of Hodgkin's disease (HD), multiple myeloma (MM), and soft tissue sarcoma (STS). Farm residence or work was reported by 38% (n = 119) of HD, 45% (n = 178) of MM, 43% (n = 156) of STS cases and 45% (n = 673) of controls. We conducted conditional logistic regression analyses and report odds ratios (OR(adj)) and 95% confidence intervals. After adjustment for covariates, exposure to farm animals had minimal effect on risk. The independent risk factors after adjustment for covariates were a family history of cancer (MM, STS), occupational uranium exposure (HD), professional driving (MM), and personal previous cancer (MM) or shingles (HD, MM).

Familial invasive and borderline ovarian tumors by proband status, age and histology

Age-specific familial risks in ovarian cancer have not been assessed by histologic types of medically verified cancers. We used the nationwide Swedish Family-Cancer Database on 10.2 million individuals and 19,175 invasive and 3,436 borderline ovarian cancers to calculate, by affected family members, standardized incidence ratios (SIRs) and 95% confidence intervals (CIs) for familial ovarian cancer in 0-66 year old daughters. SIRs for all invasive ovarian cancer were 2.68 (95% CI 2.22-3.21) by ovarian cancer in mother, 2.94 (1.40-5.94) by an affected sister and 24.03 (6.12-74.46) by both an affected mother and sister. The population-attributable fraction from mothers was 2.52%. Seropapillary cystadenocarcinoma showed the highest familial risk, but the effect of histopathol subtype could not be fully assessed because of lack of data in probands. Age-specific data showed some early-onset components and an unusual maximal incidence in the 40s. A comparison to an earlier study on BRCA1/2 mutation analysis and relative risks of ovarian and breast cancer suggests that these mutations could account for 26% of the familial aggregation of ovarian cancer. Histopathology and age of onset appear to be important attributes of familial ovarian cancer, suggesting that further gene identification efforts should target a specific histopathology in early-onset patients.

Oligogenic segregation analysis of hereditary prostate cancer pedigrees: evidence for multiple loci affecting age at onset

Previous studies have suggested strong evidence for a hereditary component to prostate cancer (PC) susceptibility. Here, we analyze 3,796 individuals in 263 PC families recruited as part of the ongoing Prostate Cancer Genetic Research Study (PROGRESS). We use Markov chain Monte Carlo (MCMC) oligogenic segregation analysis to estimate the number of quantitative trait loci (QTLs) and their contribution to the variance in age at onset of hereditary PC (HPC). We estimate 2 covariate effects: diagnosis of PC before and after prostate-specific antigen (PSA) test availability, and presence/absence of at least 1 blood relative with primary neuroepithelial brain cancer (BC). We find evidence that 2 to 3 QTLs contribute to the variance in age at onset of HPC. The 2 QTLs with the largest contribution to the total variance are both effectively dominant loci. We find that the covariate for diagnosis before and after PSA test availability is important. Our findings for the number of QTLs contributing to HPC and the variance contribution of these QTLs will be instructive in mapping and identifying these genes.

Increased risk of breast cancer in relatives of malignant melanoma patients from families with strong cancer familial aggregation

The aim of this study was to evaluate the risk of occurrence of malignancies of different site of origin in patients with malignant melanoma (MM) of the skin and their first-degree relatives from families with cancer familial aggregations with unknown pathogenetic background (CFA). We analysed tumour spectrum and age at diagnosis of malignancies in 51 families with MM/CFA. In addition, we evaluated observed frequency (OF); expected frequency (EF); and relative risk (RR) of occurrence of malignancies in these families. In all cases peripheral blood examination of common Polish founder BRCA1 mutations was performed. In 25 families, we analysed loss of heterozygosity of BRCA1 and BRCA2 genes. We identified two subgroups of cases: 22 MM/CFA families with MM diagnosed before 55 years (< or =55 MM/CFA) and 29 MM/CFA families with MM diagnosed after 55 (>55 MM/CFA). In these families we observed increased proportion of breast cancers: 17.52% in the first subgroup (mean age of diagnosis 48.5) and 12.15% in the second subgroup. The odds ratio for breast tumours occurring before 50 in < or =55 MM/CFA families was 3.71. We also observed increased numbers of liver cancers, CSU and leukaemias. OF and EF analyses revealed increased risk of occurrence of cancers of breast (OF 10.4%, EF 4.5%) and liver (OF 1.9%, EF 0.8%) in women from MM/CFA families, RR for breast tumours was approximately 3.3 in < or =55 MM/CFA families. Molecular examination of MM/CFA families revealed no alterations within the BRCA2 gene and one germline mutation of the BRCA1 gene. In conclusion, it seems to be justified to consider systematic breast surveillance beginning at the age around 35-40 years as an option in women from < or =55 MM/CFA families.

Epidemiology of Hodgkin's disease and non-Hodgkin's lymphoma

This review considers in detail the descriptive and aetiological epidemiology of Hodgkin's disease and non-Hodgkin's lymphoma (NHL), with attention to histological subcategories when the literature allows. The aetiology of Hodgkin's disease remains only partially understood. There is evidence that Epstein-Barr virus (EBV) may be involved in the causation of some cases, and clinical immune deficiency is a risk factor for a few, but the evidence is not entirely consistent and other factors may also be important in causing the EBV-associated cases of Hodgkin's disease. The cause of EBV-unassociated cases remains obscure. For NHL, although it has been shown that some cases are related to immune deficiency and chronic antigenic stimulation, and especially to EBV in the context of immune deficiency, the causation of the majority of cases remains unknown. The increasing incidence of NHL, other than that related to AIDS, is also essentially unexplained. Epidemiological investigation of the aetiology of NHL and Hodgkin's disease is making steady progress, however, and there remain leads to be followed that may result in a better understanding and hence prevention.

A systematic review and meta-analysis of familial prostate cancer risk

OBJECTIVE

To identify published studies quantifying familial prostate cancer risks in relatives of prostate cancer cases and, by meta-analysis, obtain more precise estimates of familial risk according to the family history.

METHODS

Thirteen case-control and cohort studies were identified which have reported risks of prostate cancer in relatives of prostate cancer cases. Pooled estimates of risk for various categories of family history were obtained by calculating the weighted average of the log relative risk (RR) estimates from studies.

RESULTS

The pooled RR (95% confidence interval) in first-degree relatives was 2.5 (2.2-2.8). There was evidence that this was highest in relatives of cases diagnosed before age 60 years and that RRs declined with age. The risk for the few men with two affected relatives was increased 3.5-fold (2.6-4.8). RRs to sons of cases appeared to be lower than in brothers; a complete explanation of this observation is uncertain.

CONCLUSION

Men with a family history of prostate cancer have a significantly greater risk of developing prostate cancer than those with no such history. Risks are greatest for relatives of cases diagnosed when young and those with more than one relative affected.

Subsequent primary malignancies after endometrial carcinoma and ovarian carcinoma

BACKGROUND

Population-based data on subsequent neoplasms after women are diagnosed with endometrial and ovarian carcinomas are limited, particularly regarding specific histologic tumor types.

METHODS

The nationwide Swedish Family-Cancer Database of 10.2 million individuals, which includes 19,128 invasive endometrial carcinomas and 19,440 ovarian carcinomas, was used to calculate standardized incidence ratios (SIRs) and 95% confidence intervals (95% CIs) for second primary carcinomas. SIRs were calculated for specific follow-up periods. Data on histopathologic types also were used.

RESULTS

An excess of subsequent malignancies after women were diagnosed with endometrial carcinoma was noted at 11 sites. The highest SIRs were recorded for synchronous or metasynchronous ovarian carcinomas (SIR, 55.77; 95% CI, 48.82-63.43) and carcinomas of the small intestines (SIR, 14.71; 95% CI, 4.64-34.59). Primary ovarian carcinoma was followed by an increased risk of developing endometrial carcinoma, and the risks of developing many other malignancies also were increased after women were diagnosed with endometrial carcinoma, including intestinal malignancies, renal cell carcinoma, bladder carcinoma, squamous cell skin carcinoma, connective tissue malignancies, and leukemia. When ovarian endometrioid histology was diagnosed synchronously with primary endometrial carcinoma, the SIR was 140; when endometrial carcinoma was the subsequent neoplasm, the SIR was 87. A small familial component was found in the cooccurrence of endometrial carcinoma and ovarian carcinoma.

CONCLUSIONS

The current data show a strong clustering of endometrial carcinomas and ovarian carcinomas, particularly involving tumors of endometrioid morphology. The patterns of second neoplasms also suggest that hereditary nonpolyposis colorectal carcinoma may contribute to the association between endometrial and ovarian malignancies. Increased risks for connective tissue tumors and leukemia may signal a response to treatment, and an increased risk for squamous cell skin carcinoma may signal a depressed immune function.

Incidence trends and familial risks in invasive and in situ cutaneous melanoma by sun-exposed body sites

We studied incidence trends, age-incidence relationships and familial risks in invasive and in situ cutaneous melanoma, based on the Swedish Family-Cancer Database of more than 10 million individuals. Offspring were 0-66 years of age. Cancers were obtained from the Swedish Cancer Registry from years 1961-98. The study was based on 9,771 offspring and 22,888 parents with invasive melanoma and 2,446 offspring and 5,017 parents with in situ melanoma. Incidence rates increased markedly for invasive melanoma in the trunk. For in situ melanoma, trunk and head and neck were affected, and, in addition, legs for women. The maximal incidence was around age 80 years, independent of the type or site in men; in women early onset superficially spreading melanoma shifted the age for maximal incidence to about 60 years. For in situ melanoma, lentigo maligna was the main histogenetic type in the head and neck but in the trunk and legs superficially spreading melanoma was somewhat more common. Standardized incidence ratios (SIR) were calculated for familial risk at exposed and covered sites. The combined familial risks for invasive and in situ melanoma were higher at covered (SIR 3.56 from parents) than sun-exposed (1.92 from parents) sites and they agreed when familiality was defined between parents and offspring or between siblings; the sibling SIRs were 3.90 at covered and 2.53 at exposed sites. The data suggest that the higher melanoma density at exposed sites masks familial effects. Furthermore, sun exposure does not appear to reinforce the familial effect.

Risk factors for colorectal cancer following breast cancer

OBJECTIVE

To investigate risk factors for colorectal cancer following breast cancer.

METHODS

In this nested case-control study, all women (n = 14,900) with a first primary breast cancer (1978-1992) were identified from the western Washington population-based Surveillance, Epidemiology, and End Results Cancer Registry. Cases (n = 160) developed a second primary colorectal cancer before 1995, at least 6 months after the first cancer diagnosis. Controls (n = 310, matched to the cases on calendar year, age and breast cancer stage) were randomly selected from those who did not develop a second primary cancer and who survived to the case's colorectal cancer diagnosis date. Characteristics of the cases and controls at initial diagnosis were compared using conditional logistic regression.

RESULTS

The incidence of colorectal cancer was associated with a family history of breast cancer (v.s. no family history, matched odds ratio (mOR) = 2.1, 95% confidence interval (CI): 1.1-4.1), high body mass index (> or = 30kg/m2 v.s. < 30kg/m2, mOR = 2.2, CI: 1.2-3.9), and lobular breast cancer histology (v.s. ductal, mOR = 2.0, CI: 0.9-4.4). Risk was unrelated to menopausal status, prior hormone replacement therapy and estrogen/progesterone receptor status of the breast tumors.

CONCLUSIONS

The risk of developing a second primary colorectal cancer may be elevated among certain subsets of breast cancer patients.

Familial upper aerodigestive tract cancers: incidence trends, familial clustering and subsequent cancers

Familial risks in upper aerodigestive tract cancer have been assessed mainly through case-control studies based on reported but not medically verified cancers in family members. The nationwide Swedish Family-Cancer Database was used to describe the incidence trends for all subsites of upper aerodigestive tract cancer and to calculate standardized incidence ratios (SIRs) and 95% confidence intervals (CIs) for the cancer in 0-66-year-old offspring by cancers in family members. Additionally, SIRs for second primary cancer after upper aerodigestive tract cancers were analysed. SIRs in offspring for all upper aerodigestive tract cancer were not significant when a parent presented with concordant cancer. The population attributable fraction of familial upper aerodigestive tract cancer was 0.43%. Risk for subsequent cancers in men and women after upper aerodigestive tract cancer were increased in smoking, alcohol and other life-style related sites and in skin cancer and non-Hodgkin's lymphoma.

Genetic counseling for prostate cancer risk

Major risk factors for developing prostate cancer, including positive family history and African-American ethnicity, can be quantified for genetic counseling. Factors increasing familial risk for prostate cancer are closer degree of kinship, number of affected relatives, and early age of onset (< 50 years) among the affected relatives. Genetic testing may be useful for modification of risk, but currently should be performed only within the context of a well-designed research study that will determine penetrance and genotype-phenotype correlation of specific mutations. Even in the absence of genetic testing, African-American men and men with a strong family history of prostate cancer may opt to initiate screening by prostate specific antigen (PSA) and digital rectal exam (DRE) screening at age 40.

Genetic screening for hereditary diffuse gastric cancer

Knowledge regarding the genetic basis of hereditary diffuse gastric cancer has greatly increased in the past 4 years, namely due to the discovery of segregating germline mutations in the gene coding for E-cadherin, within families with this cancer predisposing syndrome. Members of hereditary diffuse gastric cancer families have predominantly high predisposition to develop diffuse carcinomas of the stomach but can also be associated with an elevate risk for other types of cancer, namely lobular breast carcinoma. In this review, we focus on the epidemiology, pathology and genetics of gastric cancer, describe families, E-cadherin mutations, and suggest alternative candidate genes underlying the hereditary diffuse gastric cancer syndrome. This knowledge is a fundamental step towards accurate genetic counselling, in which a highly specialized presymptomatic therapeutic intervention should be offered.

Family history of cancer and risk of ovarian cancer

The aim of this study was to examine the relationship between history of cancer in first-degree relatives and ovarian cancer risk. Between 1992 and 1999, we conducted a case-control study in Italy on 1031 women with epithelial ovarian cancer and 2411 women admitted to hospital for acute non-neoplastic conditions. Odds ratios (OR) were estimated using unconditional logistic regression, adjusted for age and several potential confounders. Overall, 27 cases and nine controls reported a family history of ovarian cancer (OR = 7.0; 95% confidence interval (CI) 3.1-16). The OR was 23 (95% CI 2.6-212) below age 50 years, based on 10 cases and one control only. The risk of ovarian cancer was also increased in women with a family history of cancer of the stomach (OR = 1.5; 95% CI 1.0-2.1), intestine (OR = 1.7; 95% CI 1.2-2.4), lung (OR = 1.3; 95% CI 1.0-1.8), breast (OR = 2.3; 95% CI 1.7-3.1), lymphomas (OR = 2.3; 95% CI 1.0-5.1) and all sites (OR = 1.6; 95% CI 1.4-1.9). Our results confirm the higher ovarian cancer risk in women with a family history of ovarian and breast cancer, and suggest a few associations with other sites.

Familial and second lung cancers: a nation-wide epidemiologic study from Sweden

The role of hereditary factors in tumor development has been less well understood for lung cancer than for many other human neoplastic diseases. The nation-wide Swedish Family-Cancer Database was used on 10.2 million individuals and 4524 lung cancers to calculate standardized incidence ratios (SIRs) and 95% confidence intervals (CIs) for histological subtypes of lung cancer in 0-66-year-old offspring by cancers in family members. Additionally, SIRs for second lung cancers were analyzed. SIRs in offspring for all lung cancer were increased to 1.87 (95% CI 1.66-2.10), adenocarcinoma to 2.15 (1.77-2.59) and squamous cell carcinoma to 1.86 (1.39-2.44) when a parent presented with lung cancer. The familial risk was not dependent on diagnostic age. Lung cancer associated with parental rectal, cervical, kidney, urinary bladder and endocrine gland cancer. The population attributable fraction of familial lung cancer was 2.97%. Risks for second lung cancers were increased in men and women after smoking and life style related sites, and after skin cancer, non-Hodgkin's lymphoma and Hodgkin's disease.

B-cell monoclonal lymphocytosis and B-cell abnormalities in the setting of familial B-cell chronic lymphocytic leukemia

BACKGROUND

Among all hematologic malignancies, B-cell chronic lymphocytic leukemia (BCLL) has the highest familial clustering (three- to sevenfold increase), strongly suggesting a genetic component to its etiology. Familial BCLL can be used as a model to study the early pathogenesis of this disease.

METHODS

We examined nine kindreds from the National Cancer Institute's Familial BCLL Registry, consisting of 19 affected members with BCLL and 33 clinically unaffected first-degree relatives. Flow cytometric immunophenotyping to detect a B-cell monoclonal lymphocytosis (BCML) was performed. Monoclonality was confirmed by polymerase chain reaction analysis of whole blood DNA. Cell cycle analysis for aneuploidy was conducted.

RESULTS

In all affected individuals, we observed the classic BCLL CD5/CD19/CD20/CD23 immunophenotypic patterns. Six of the 33 unaffected individuals (18%) had evidence of BCML. Additional individuals (13/33, 39%) showed some other abnormality, whereas 14 individuals (42%) were normal. Based on an estimated prevalence of 0.7% for BCML in the general population, the finding of six subjects (18%) with clonal abnormalities in this relatively modest sample was significantly greater than expected (i.e., 18% vs. 0.7%, P < 5.7 x 10(-9)).

CONCLUSIONS

Individual components of BCML and other B-cell abnormalities were observed in almost half of the apparently unaffected individuals. Our findings suggested that BCML may be an early detectable abnormality in BCLL. The spectrum of some of these observed abnormalities suggested the involvement of different B-cell subpopulations or different pathways in clonal evolution. Population-based, longitudinal studies will be required to determine the incidence of BCML and other B-cell abnormalities and their relation to disease progression in BCLL and other closely related B-cell lymphoproliferative disorders.

Confirmation of linkage of prostate cancer aggressiveness with chromosome 19q

Regions on chromosomes 7 and 19 were recently reported to contain susceptibility loci that regulate tumor aggressiveness of prostate cancer. To confirm these findings, we analyzed genome scan data from 161 pedigrees affected with prostate cancer. Using the Gleason score as a quantitative measure of tumor aggressiveness, we regressed the squared trait difference, as well as the mean-corrected cross product, on the estimated proportion of alleles shared identical-by-descent at each marker position. Our results confirm the previous linkage results for chromosome 19q (D19S902, P<.00001). In addition, we report suggestive evidence for linkage on chromosome 4 (D4S403, P=.00012). The results of previous findings, together with our results, provide strong evidence that chromosome 19 harbors a gene for tumor aggressiveness.

Familial and second primary pancreatic cancers: a nationwide epidemiologic study from Sweden

Familial risk of pancreatic cancer has been mainly assessed through case-control studies based on reported but not medically verified cancers in family members. We used the nationwide Swedish Family-Cancer Database on 10.2 million individuals and 21,000 pancreatic cancers to calculate standardized incidence ratios (SIRs) and 95% confidence intervals (CIs) for pancreatic cancer in 0- to 66-year-old offspring of parents with pancreatic or other specified tumors. Additionally, SIRs for second primary pancreatic cancers were analyzed after any first neoplasm. SIRs for pancreatic cancer (1.68, 95% CI 1.16-2.35) and pancreatic adenocarcinoma (1.73, 95% CI 1.13-2.54) were increased when a parent presented with pancreatic cancer. The risk was not dependent on diagnostic age of offspring or parents. Pancreatic cancer was associated with parental lung, rectal or endometrial cancer and with melanoma. SIRs for pancreatic cancer were 10.01 and 7.96 among offspring who were diagnosed before age 50 years when parents were diagnosed with squamous cell and adenocarcinoma of the lung, respectively, before age 60 years. The population-attributable proportion of familial pancreatic cancer was 1.1%. Risks for second pancreatic cancers were increased in men and women after small intestinal, colon and bladder cancer. The degree of familial clustering for pancreatic cancer and its population-attributable proportion were lower than the data cited in the literature. Clustering of pancreatic cancer with sites presenting in hereditary nonpolyposis colorectal cancer was noted. The strong association of pancreatic and lung cancers is puzzling, and it remains unclear to what extent this represents familial sharing of smoking habits.

Squamous cell carcinoma of the oral cavity in patients aged 45 years and under: a descriptive analysis of 116 cases diagnosed in the South East of England from 1990 to 1997

BACKGROUND

there is, currently, much anecdotal and some epidemiological evidence for a rise in oral cancer rates amongst younger individuals, many of whom have had no exposure to traditional risk factors such as tobacco and heavy alcohol use, or at least not the exposure over decades usually associated with this disease. The probity of this assertion and the presence or absence of traditional risk factors needs further evidence.

OBJECTIVES

this paper describes the demography and the exposure to potential risk factors amongst a cohort aged 45 years and younger, diagnosed with squamous cell carcinoma of the oral cavity between 1990 and 1997 from the South East of England.

MATERIALS AND METHODS

eligible patients registered with a cancer registry were included in this retrospective study. Information was accessed from the database and by a postal questionnaire survey. The self-completed questionnaire contained items about exposure to the following risk factors: tobacco; alcohol; diet; frequency of dental visits and familial cancer.

RESULTS AND CONCLUSIONS

this is the largest UK epidemiological study so far to be undertaken on young subjects diagnosed with oral cancer. One-hundred and sixteen cases were recruited representing a response rate of 59%. Slightly over 90% of this cohort were classified as white European. A large proportion of cases (40%) were from social classes I & II suggesting either a true social class difference in young cases versus older oral cancer cases or a possible bias in responders or survivors. Risk factors of tobacco use and excessive alcohol consumption were present in the majority (75%) of patients. Significant differences in the pattern of alcohol consumption were found in female subjects, who were less likely to consume over the recommended amounts of alcohol compared with male subjects. Daily regular fresh fruit and vegetable consumption during the ten year period before cancer diagnosis was recorded to be low. There was a distinct subgroup of cases, 26% of the group, that showed little, if any, exposure to any major risk factors.

Familial and attributable risks in cutaneous melanoma: effects of proband and age

We studied familial risks in invasive and in situ cutaneous melanoma by comparing the occurrence of melanoma, or discordant cancer, between parents and offspring, and between siblings, based on the Swedish Family Cancer Database of over 10 million individuals. Offspring were 0-66 y of age. Cancers were obtained from the Swedish Cancer Registry from 1961 to 1998. The study was based on 24,818 invasive and 5510 in situ cases of melanoma. Standardized incidence ratios were calculated for familial risk. The standardized incidence ratios for offspring was 2.40 (95% confidence intervals: 2.10-2.72) when only the parent had melanoma and it was 2.98 (95% confidence intervals: 2.54-3.47) when only a sibling was affected; when both a parent and a sibling were affected the standardized incidence ratios was 8.92 (95% confidence intervals: 4.25-15.31). The respective population attributable risks were 1.38, 1.20, and 0.10%. The familial risk showed a clear age dependence and somewhat higher risk in in situ melanoma than in the invasive counterpart. The highest standardized incidence ratio of 61.78 (5.82-227.19) was noted for offspring whose parent had multiple melanomas. Superficially spreading melanoma showed the highest familial risk both among invasive and in situ tumors. Melanoma associated with breast, nervous system, and skin cancers, and in situ melanoma possibly also with connective tissue and thyroid tumors and multiple myeloma.

Familial risk of cancer: Data for clinical counseling and cancer genetics

Familial risks for cancer are important for clinical counseling and understanding cancer etiology. Medically verified data on familial risks have not been available for all types of cancer. The nationwide Swedish Family-Cancer Database includes all Swedes born in 1932 and later (0-to 68-year-old offspring) with their parents, totaling over 10.2 million individuals. Cancer cases were retrieved from the Swedish Cancer Registry up to year 2000. Standardized incidence ratios (SIR) and 95% confidence limits (CI) were calculated for age-specific familial risk in offspring by an exact proband status. The familial risks for offspring cancer were increased at 24/25 sites from concordant cancer in only the parent, at 20/21 sites from a sibling proband and at 12/12 sites from a parent and sibling proband. The highest SIRs by parent were for Hodgkin's disease (4.88) and testicular (4.26), non-medullary thyroid (3.26), ovarian (3.15) and esophageal (3.14) cancer and for multiple myeloma (3.33). When a sibling was affected, even prostate, renal, squamous cell skin, endocrine, gastric and lung cancer and leukemia showed SIRs in excess of 3.00. The highest cumulative risks were found for familial breast (5.5%) and prostate (4.2%) cancers. We identified reliable familial risks for 24 common neoplasms, most of which lack guidelines for clinical counseling or action level. If, for example, a familial SIR of 2.2 would be use as an action level, counseling would be needed for most cancers at some diagnostic age groups. The present data provide the basis for clinical counseling.

Oxyphilic carcinoma of the thyroid gland

Oxyphilic tumors of the thyroid gland are rare tumors characterized by the presence of H?rthle cells - mitochondrion-rich, eosinophilic epithelial cells. H?rthle cell carcinomas (HCC) of the thyroid behave in a more aggressive fashion as compared to other well-differentiated thyroid cancers. Many recent studies have been focused on the further elucidation of pathogenesis and the role of mitochondrial hyperplasia in carcinogenesis of these neoplasms. The importance of combining morphological and genetic approaches in the study of HCC has been emphasized by the difficulties encountered in establishing adequate differential diagnostic criteria between benign and malignant forms, as well as by the resistance of HCC to radio and chemotherapy. It has been well documented that the H?rthle cells are characterized by profound aberrations in the nuclear and mitochondrial genome and by alterations in oncogenes, tumor suppressor genes and other key genes involved in energy metabolism, proliferation and apoptosis.

Familial risk of cancer by site and histopathology

Familial risks for histopathology-specific cancers have not been determined. We used the nationwide Swedish Family-Cancer Database on 10.2 million individuals and 1 million tumors to calculate standardized incidence ratios (SIRs) for familial cancers of specific histology and morphology among 0- to 66-year-old offspring. We used histology codes for both offspring and parents, but because of the limited number of cases, the morphology-specific classification could be used only for offspring by all site-specific cancers in parents, resulting in inflated risk estimates. A number of novel findings emerged in the histopathology-specific analysis of familial risks, in addition to some known associations. Overall, specific histology showed an SIR of 2.07 for all cancers compared to an SIR of 2.00 for any histology. However, the small effect was due to breast and prostate cancers, which showed a negligible effect of specific histology. Familial risks of over 4.0 were found for serous papillary cystadenocarcinoma of the ovary, papillary thyroid cancer and low-grade astrocytoma. Familial risks of over 3.0 were found for signet-ring gastric cancer, various forms of ovarian cancer and squamous cell skin cancer. Also noteworthy were familial risks of hepatocellular carcinoma (2.48), pancreatic adenocarcinoma (1.92), large cell carcinoma and adenocarcinoma of the lung (2.29 and 2.18, respectively) and clear cell carcinoma of the kidney (2.73). Many of the findings were novel and could be revealed only by applying codes for specific histopathology. These data call for a closer description of familial aggregations and probing for the underlying genetic mechanisms.

Cytogenetics and molecular genetics of ovarian cancer

Genetic alterations identified in human ovarian tumors by conventional banding, fluorescence in situ hybridization, comparative genomic hybridization, chromosome microdissection, loss of heterozygosity, chromosome microcell-mediated chromosome transfer, and microarray gene expression analysis are summarized and correlated. The significance of these findings with respect to pathologic classification and clinical application are discussed.

Age specific and attributable risks of familial prostate carcinoma from the family-cancer database

BACKGROUND

Familial risks by proband status and age are useful for clinical counseling, and they can be used to calculate population-attributable fractions (PAFs), which show the proportion of disease that could be prevented if the cause could be removed.

METHODS

The authors used the nationwide Swedish Family-Cancer Database on 10.2 million individuals and 182,104 fathers and 3710 sons with medically verified prostate carcinoma to calculate age specific familial standardized incidence ratios (SIRs) with 95% confidence intervals (95%CI) and familial PAFs for prostate carcinoma in sons ages 0-66 years.

RESULTS

The incidence of prostate carcinoma was doubled between the years 1961 and 1998. The familial SIRs for prostate carcinoma were 2.38 (95%CI, 2.18-2.59) for men with prostate carcinoma in the father only, 3.75 (95%CI, 2.73-4.95) for men with prostate carcinoma in a brother only, and 9.44 (95%CI, 5.76-14.03) for men with prostate carcinoma in both a father and a brother. The corresponding familial PAFs were 8.86%, 1.78%, and 0.99%, respectively, yielding a total PAF of 11.63%. Age specific risks were shown for the same proband histories. The SIR was 8.05 for prostate carcinoma before age 55 if a brother had been diagnosed before that age. If, in addition, a father was diagnosed at any age, then the SIR was 33.09.

CONCLUSIONS

The authors recommend that having a brother who is diagnosed with prostate carcinoma before age 55 years or having a brother and father who are diagnosed at any age are indications to screen for prostate carcinoma. The familial PAF of prostate carcinoma among a population of sons ages 0-66 years was 11.63%.

Myeloma aetiology and epidemiology

Recently there have been substantial improvements in our understanding of the biology of myeloma. These findings have important implications for aetiological studies aimed at defining the causative factors for myeloma. Myeloma is closely related to monoclonal gammopathy of unknown significance (MGUS), which is now recognized to be very common in the older population. The epidemiology of these conditions is presented and discussed in the context of the genetic factors governing both the risk of developing MGUS or of transformation to myeloma. Biological studies support a role for aberrant class switch recombination early in the natural history of myeloma suggesting that factors in the environment may interact with this mechanism to increase myeloma risk. Case-control and cohort studies have identified several known and suspected environmental exposures. These exposures include high doses of ionizing radiation, and occupational exposure in the farming and petrochemical industries. The data supporting these associations are presented and discussed in the context of the molecular mechanisms underlying these exposures. In particular DNA damage occurring as a consequence could readily interact with the class switch recombination process to increase the risk of chromosomal translocations, oncogene deregulation and malignant transformation. A further hypothesis, which has been extensively investigated, is the role of chronic immune/antigenic stimulation and the risk of myeloma. This concept is difficult to explain in the context of our current immunological concepts. The data supporting the association and how molecular epidemiological studies using genetic variants in cytokine genes are allowing us to revisit this concept are discussed in detail.

The effect of a single BRCA2 mutation on cancer in Iceland

OBJECTIVE

To estimate the risk of malignant diseases in families of probands with the same mutation in the BRCA2 gene.

DESIGN

A cohort study using record linkage of a breast cancer family resource and the Icelandic Cancer Registry.

SETTING

Iceland.

SUBJECTS

Families of 995 breast cancer patients, from which 887 were tested for a single founder 999del5 mutation; 90 had the mutation and 797 did not.

RESULTS

Relatives of probands with the mutation had significantly increased relative risk (RR) of breast cancer. For first degree relatives, the RR was 7.55 (95% CI 6.04 to 9.03) but was 1.72 (95% CI 1.49 to 1.96) in first degree relatives of probands without the mutation. For prostate and ovarian cancer, the first and second degree relatives of probands with the mutation had a significantly increased RR, but in families of probands without the mutation no significant familial risk was found.

CONCLUSIONS

The 999del5 mutation in the BRCA2 gene explains a substantial proportion of familial risk of breast cancer in Iceland, but significant familial risk remains in relatives of probands without the mutation. For prostate and ovarian cancer, the mutation accounts for most of the familiality observed in families of breast cancer patients.

Analysis of the RNASEL gene in familial and sporadic prostate cancer

The RNASEL gene on chromosome 1q25 was recently identified as a candidate gene for hereditary prostate cancer (PC). To confirm these findings, we screened 326 patients from 163 families with familial PC for potential germline mutations, by use of conformation-sensitive gel electrophoresis, followed by direct sequence analysis. A total of six variants were identified, including one intronic and five exonic changes (three missense and two silent alterations). There were no unequivocal pathogenic changes. To further test for potential associations between genes and increased risk for disease, the three missense polymorphisms (Ile97Leu, Arg462Gln, and Glu541Asp) were genotyped in 438 patients with familial PC and in 510 population-based control subjects. Association testing revealed no significant differences between patients and control subjects for either the Leu97 variant (chi(2) trend test = 1.42; P=.23) or the Asp541 variant (chi2=1.52; P=.22). However, significant differences were detected for the Arg462Gln genotypes (chi2=5.20; P=.02; odds ratio [OR] = 0.54; 95% confidence interval [CI] 0.32-0.91) when the genotype Gln/Gln was compared with Arg/Arg. In subset analyses, associations were also observed in the younger group (age at diagnosis </=64 years) (P=.0008; OR=0.29; 95% CI = 0.13-0.66), in node-negative patients (P=.01; OR=0.48; 95% CI 0.27-0.84), patients with stage T(1)/T(2) disease (P=.008; OR=0.39; 95% CI 0.2-0.75), and patients with low-grade disease (P=.01; OR=0.40; 95% CI 0.20-0.78). To evaluate whether this variant was also associated with sporadic PC, we genotyped an additional 499 patients with sporadic PC. Differences in frequency were not detected between patients with sporadic disease and control subjects. However, the same association was observed between patients with familial disease and patients with sporadic disease for the entire group (chi2=4.82; P=.03), as well as in the subset analyses. These results suggest that polymorphic changes within the RNASEL gene may be associated with increased risk of familial but not sporadic PC.

Cancer risks among long-standing spouses

We estimated risks for concordant and discordant cancers in spouses in order to quantify cancer risks from the shared environment. The study was restricted to spouses who had one or more children in common and who lived together for at least 15 years after the first child's birth. The nation-wide Family-Cancer Database was used as the source of family and cancer data. Standardised incidence ratios were calculated for concordant and discordant cancers in spouses after 50 years of age. Among the 18 cancer sites considered, only three sites, stomach, lung and bladder, showed concordant increases of cancer among spouses, standardised incidence ratios ranging only from 1.19 to 1.38. Additionally, gastric and pancreatic cancer were associated among spouses, as did many cancers which were related to tobacco smoking or human papilloma virus infection. By contrast, standardised incidence ratios of colon, rectal, renal and skin cancers showed no increases among spouses. Shared lifestyle among family members seems to explain only a small proportion of familial cancer susceptibility. Because lifestyles are likely to differ more between parents and offspring than between spouses, familial cancer risks between parents and offspring are even more likely to be due to heritable than environmental effects.

Family history and prostate cancer screening with prostate-specific antigen

PURPOSE

Early detection of prostate cancer has been recommended for men with affected first-degree relatives despite the lack of evidence for mortality reduction. We therefore evaluated the impact of family history in the Finnish prostate cancer screening trial.

PATIENTS AND METHODS

Approximately 80,000 men were identified from the population register for the first screening round. Of the 32,000 men randomized to the screening arm, 30,403 were eligible at the time of invitation. A blood sample was drawn from the participants (n = 20,716), and serum prostate-specific antigen (PSA) was determined. Men with a PSA level > or = 4.0 ng/mL were referred for prostate biopsy. Information on family history was obtained through a self-administered questionnaire at baseline.

RESULTS

A total of 964 (5%) of the 20,716 screening participants had a positive family history, and 105 (11%) were screening-positive. Twenty-nine tumors were diagnosed, corresponding to a detection rate of 3.0% (29 of 964) and a positive predictive value of 28% (29 of 105). Of the 19,347 men without a family history, 1,487 (8%) had a PSA level > or = 4.0 ng/mL. The detection rate was 2.4% (462 of 19,347) and the positive predictive value was 31% (462 of 1,487). The risk associated with a positive family history was not substantially increased (rate ratio, 1.3; 95% confidence interval, 0.9 to 1.8). The results were not affected by the age of the screenee or age at diagnosis of the affected relative. The program sensitivity was 6% (29 of 491) (ie, selective screening policy would have missed 94% of cancers in the population). No differences were seen in the characteristics of screen-detected cancers by family history.

CONCLUSION

Our findings provide no support for selective screening among men with affected relatives.