Familial clustering of colon, breast, uterine, and ovarian cancers as assessed by family history

Preliminary Results: Colorectal Cancer Screening Using Fecal Immunochemical Test (FIT) in a Thai Population Aged 45-74 Years: A Population-Based Randomized Controlled Trial

Objective:

The aim of this paper is to provide some details and the results to date of a colorectal cancer screening trial using a fecal immunochemical test (FIT).

Methods:

A population-based randomized controlled trial began in May, 2016. All people aged 45 to 74 years living in Nam Phong District, Khon Kaen Province, Thailand, and willing to participate are being recruited using an outreach method. Enrolled participants are randomly allocated by a computer-generated randomization program either to a study arm (receive sample kit for FIT) or to a control arm (no provision of kit). Positive FIT cases are subsequently confirmed by a colonoscopy examination, and negative FIT cases are re-tested with FIT every two years. The preliminary results to date were analysed using descriptive statistics.

Results:

A total of 1,060 enrolled participants provided a complete set of data. Of those randomly assigned to the study arm and tested by FIT, 92 (8.7%) were found to be positive, 39 (11.5%) males and 53 (7.4%) females. The f-Hb concentrations at the 75th, 90th and 95th percentiles for all age groups were higher in males than in females, and the distributions of f-Hb concentration varied with age, especially at the 95th percentile where f-Hb concentrations increased with age.

Conclusion:

The preliminary results of our screening trial have indicated that the prevalence of positive FIT cases is higher than in a similar recent and, at the time unique, previous study in Thailand. This finding is especially the case for males and those in the older age groups.

Family history and the natural history of colorectal cancer: systematic review

PURPOSE

Family history of colorectal cancer (CRC) is a known risk factor for CRC and encompasses both genetic and shared environmental risks.

METHODS

We conducted a systematic review to estimate the impact of family history on the natural history of CRC and adherence to screening.

RESULTS

We found high heterogeneity in family-history definitions, the most common definition being one or more first-degree relatives. The prevalence of family history may be lower than the commonly cited 10%, and confirms evidence for increasing levels of risk associated with increasing family-history burden. There is evidence for higher prevalence of adenomas and of multiple adenomas in people with family history of CRC but no evidence for differential adenoma location or adenoma progression by family history. Limited data regarding the natural history of CRC by family history suggest a differential age or stage at cancer diagnosis and mixed evidence with respect to tumor location. Adherence to recommended colonoscopy screening was higher in people with a family history of CRC.

CONCLUSION

Stratification based on polygenic and/or multifactorial risk assessment may mature to the point of displacing family history-based approaches, but for the foreseeable future, family history may remain a valuable clinical tool for identifying individuals at increased risk for CRC.

Lynch syndrome caused by MLH1 mutations is associated with an increased risk of breast cancer: a cohort study

INTRODUCTION

Lynch syndrome is known to cause an increased risk of malignancies, including bowel and endometrial cancers. However, the risk of breast cancer associated with mutations in the mismatch repair (MMR) genes that cause Lynch syndrome is still unclear.

MATERIALS AND METHODS

This study assesses the cumulative risk of breast cancer in 106 MLH1 and 118 MSH2 families. Families were referred on the basis of clinical criteria. Pedigree information was obtained, and tumour immunohistochemistry and microsatellite testing performed. Appropriate patients underwent sequencing and multiple ligation dependent probe amplification of all relevant exons of the MMR genes. Kaplan-Meier analysis of cumulative lifetime risk of breast cancer was made combining proven mutation carriers and their first-degree female relatives.

RESULTS

After allocation of mutation status, the cumulative risk of breast cancer to 70 years in MLH1 carriers was 18.6% (95% CI 11.3 to 25.9)). This is significantly higher than the cumulative risk for MSH2 which was 11.2% (95% CI 1.4 to 21.0) to age 70 years (p=0.014). The UK population risk is 7.5%-8% at the age of 70 years. Prospective analysis identified six breast cancers in 1120 years of follow-up with an OR of 3.41 (95% CI 1.53 to 7.59).

DISCUSSIONS

Female MLH1 carriers would appear to be at moderate risk of breast cancer and should be considered for breast screening at ages earlier than national screening programmes.

Does risk of endometrial cancer for women without a germline mutation in a DNA mismatch repair gene depend on family history of endometrial cancer or colorectal cancer?

OBJECTIVE

To determine whether risk of endometrial cancer for women without a germline mutation in a DNA mismatch repair (MMR) gene depends on family history of endometrial or colorectal cancer.

METHODS

We retrospectively followed a cohort of 79,166 women who were recruited to the Colon Cancer Family Registry, after exclusion of women who were relatives of a carrier of a MMR gene mutation. The Kaplan-Meier failure method was used to estimate the cumulative risk of endometrial cancer. Cox regression was used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for association between family history of endometrial or colorectal cancer and risk of endometrial cancer.

RESULTS

A total of 628 endometrial cancer cases were observed, with mean age at diagnosis of 54.4 (standard deviation: 15.7) years. The cumulative risk of endometrial cancer to age 70 years was estimated to be 0.94% (95% CI 0.83-1.05) for women with no family history of endometrial cancer, and 3.80% (95% CI 2.75-4.98) for women with at least one first- or second-degree relative with endometrial cancer. Compared with women without family history, we found an increased risk of endometrial cancer for women with at least one first- or second-degree relative with endometrial cancer (HR 3.66, 95% CI 2.63-5.08), and for women with one first-degree relative with colorectal cancer diagnosed at age <50 years (HR 1.48, 95% CI 1.15-1.91).

CONCLUSION

An increased risk of endometrial cancer is associated with a family history of endometrial cancer or early-onset colorectal cancer for women without a MMR gene mutation, indicating for potential underlying genetic and environmental factors shared by colorectal and endometrial cancers other than caused by MMR gene mutations.

Breast cancer risk scores in a standard screening population

SUMMARY Aim: Information regarding the characteristics and breast cancer risk factors of British women in the standard population attending breast cancer screening is limited. Such information could be useful in personalizing screening and care, and informing and educating women about their risk. Materials & methods: Information about various breast cancer risk factors was obtained from 355 women aged between 46 and 74 years at a UK inner-city breast cancer screening clinic using questionnaires. The risk of breast cancer was calculated using the modified Gail model and analyzed using descriptive and regression statistics. Results: There were 26 women recalled for further assessment and two cases confirmed as invasive breast cancer. Forty-seven women reported first-degree relatives with breast cancer. A total of 58% of our sample was overweight or obese, although 84% reported meeting the recommended target of ≥150 min of exercise per week. A total of 44% were smokers and 23% reported consuming alcohol on a regular basis. The mean lifetime risk score was 9.0% and the mean 5-year risk score was 1.5%. Various non-Gail model risk factors were found to be correlated with risk scores, but the only factor that was significantly different between women recalled for further assessment and those who were not was age of menarche. Conclusion: The results suggest that determining risk factor data in a standard screening population could be useful both to the women, who may have modifiable lifestyle factors that can be changed to improve their risk, and to the clinics, which can identify women at a higher risk who may be unaware and not present themselves as candidates for risk assessment.

Endometrial cancer and a family history of cancer

OBJECTIVE

Lynch Syndrome (LS), an inherited genetic syndrome, predisposes to cancers such as colorectal and endometrial. However, the risk for endometrial cancer (EC) in women not affected by LS, but with a family history of cancer, is currently unknown. We examined the association between a family history of cancer and the risk for EC in non-LS patients.

METHODS

This population-based case-control study included 519 EC cases and 1015 age-matched controls and took place in Alberta, Canada between 2002 and 2006. Information about risk factors, including family history of cancer in first and second degree relatives, was ascertained via in-person interviews. Microsatellite instability (MSI) status of tumor tissue was assessed to determine involvement of DNA mismatch repair (MMR) genes.

RESULTS

A first or second degree family history of uterine cancer was modestly associated with the risk for overall EC [odds ratio (OR), 1.3; 95% confidence interval (CI), 0.9, 1.9], and the risks were similar for MSI+cancer (OR=1.5, 95%CI=0.7, 3.3) and MSI- cancer (OR=1.3, 95%CI=0.8, 2.4). Although consistent, these associations were modest and not significant. In contrast, the risk for MSI+cancer was elevated with a reported family history of colorectal cancer (OR=1.4, 95%CI=1.0, 2.2), but not for MSI- cancer.

CONCLUSIONS

A family history of uterine cancer may be modestly associated with EC risk in non-LS patients regardless of MSI status, suggesting that risk was not related to inherited defects in the MMR gene pathway. These results provide preliminary support for an EC-specific genetic syndrome.

Frequency of extracolonic tumors in Brazilian families with Lynch syndrome: analysis of a hereditary colorectal cancer institutional registry

Lynch syndrome (LS) is caused by inherited germline mutations in mismatch repair (MMR) genes. It is one of the commonest forms of inherited predisposition to colorectal cancer (CRC), accounting for 2-5% of all CRC. LS is characterized by early age of onset, with a tendency for multiplicity and an increased risk for extra-colonic tumors at particular sites. In this study we have evaluated the frequency of extra-colonic tumors in 60 unrelated LS families fulfilling the Amsterdam criteria (ACI. ACII) from the Oncotree database of the Hereditary Colorectal Cancer Registry of the AC Camargo Hospital. All families' pedigree was extensively analyzed, varying from 2 to 6 generations with a total of 2,095 individuals evaluated. As expected, colorectal cancer was the most frequent tumor in the families (334 cases). We found 200 extracolonic tumors among all individuals with a higher ratio in women (123 cases) than men (77 cases). By far, breast cancer (32 cases) was the most frequent extracolonic manifestation in women followed by endometrial (20 cases) and uterine cervix cancer (20 cases). For man, prostate (16 cases) and stomach (12 cases) cancer were the most frequent extracolonic tumors. It is well know that establishing the diagnosis is challenging and requires knowledge and surveillance. Thus, recognition of individuals and families with hereditary predisposition to cancer according to clinical and molecular features, combined with intensive surveillance and management programs, can contribute substantially to improve results related to the diagnosis and characterization of LS.

Family history of hormonal cancers and colorectal cancer risk: a case-control study conducted in Ontario

Aggregation of cancers among families with highly penetrant genetic mutations such as hereditary nonpolyposis colorectal cancer is well-described. However, there is a paucity of data regarding familial aggregation of hormonal cancers (cancers of the breast, endometrial, ovarian and prostate) and colorectal cancer (CRC) in the general population. We investigated the association between having a first-degree family history of breast, endometrial, ovarian, or prostate cancer and CRC risk. Population-based CRC cases and controls were recruited by the Ontario Familial Colorectal Cancer Registry (OFCCR). Logistic regression was conducted to obtain odds ratio (OR) estimates and 95% confidence intervals (95% CIs). First-degree family history of breast cancer was associated with a modest, borderline statistically significant increased CRC risk (age-, sex-adjusted OR = 1.2, 95% CI = 1.0, 1.5). The magnitude of CRC risk was greatest if more than one first-degree kin had breast cancer (age-, sex-adjusted OR = 1.7, 95% CI = 1.0, 2.0), as well as if the kin was diagnosed at >50 years of age (age-, sex-adjusted OR = 1.4, 95% CI = 1.1, 1.8). Family history of ovarian cancer was associated with reduced CRC risk (multivariate-adjusted OR = 0.6, 95% CI = 0.3, 1.0). Although statistically significant increases in CRC risk were observed in the age-, sex-adjusted OR estimates for family history of endometrial and prostate cancers, the associations were no longer significant after multivariate-adjustment. In conclusion, individuals with a first-degree kin with breast cancer may have a modest increased risk for CRC compared to individuals without.

Mismatch repair defective breast cancer in the hereditary nonpolyposis colorectal cancer syndrome

Whether or not breast cancer can be a feature of the hereditary nonpolyposis colorectal cancer (HNPCC) syndrome has been debated. In order to clarify if defective mismatch repair (MMR) may indeed play a role in breast cancer, we used the Danish HNPCC register to identify all breast cancers that occurred in MMR gene mutation carriers. In total, 20 female mutation carriers were diagnosed with breast cancer at mean 50 years of age. These tumors were predominantly ductal carcinomas with extensive lymphocytic reactions in 8/14 evaluated tumors. MMR protein immunostaining showed loss of expression of MLH1, MSH2 or MSH6 corresponding to the mutations identified in 7 of the 16 cases investigated, and these tumors were diagnosed at mean 50 (33-66) years of age. The demonstration of defective MMR in a substantial proportion of the breast cancers studied links yet another tumor type to HNPCC. Though the low number do not motivate surveillance, our observation supports a role for defective MMR in breast cancer progression in HNPCC, presumably through accelerated accumulation of mutations in breast cancer-associated genes.

Analysis of co-aggregation of cancer based on registry data

OBJECTIVE

An exploratory analysis of co-aggregation of cancers using registry-based data.

METHODS

We utilized sibships from over 18,000 families who had been recruited to the NCI-sponsored multi-institutional Cancer Genetics Network. The analysis assesses co-aggregation at the individual and family level and adjusts for ascertainment.

RESULTS

We found statistically significant familial co-aggregation of lung cancer with pancreatic (adjusted p < 0.001), prostate (adjusted p < 0.003), and colorectal cancers (adjusted p = 0.004). In addition, we found significant familial co-aggregation of pancreatic and colorectal cancers (adjusted p = 0.018), and co-aggregation of hematopoietic and (non-ovarian) gynecologic cancers (adjusted p = 0.01).

CONCLUSION

This analysis identified familial aggregation of cancers for which a genetic component has yet to be established.

Relative and absolute risk of colorectal cancer for individuals with a family history: A meta-analysis

Accurate risk estimates for individuals with a family history of colorectal cancer are important for surveillance strategies. We systematically reviewed the literature on familial risks of colorectal cancer to determine relative risk estimates for categories of family history and translated these relative risk estimates into absolute risk estimates. A random-effects meta-analysis pooled the effect estimates from individual studies and actuarial life-table methods converted relative into absolute risks. Fifty-nine studies were identified including 47 that estimated the relative risk of developing colorectal cancer given at least one affected first-degree relative. The pooled risk estimate was 2.24 (95% CI 2.06 to 2.43) which rose to 3.97 (95% CI 2.60 to 6.06) with at least two affected relatives. A population lifetime risk of 1.8% for a 50-year old increased to 3.4% (95% CI 2.8 to 4.0) with at least one affected relative or 6.9% (95% CI 4.5 to 10.4) with two or more. Accurate absolute risk estimates show how cancer risks vary over time, particularly by pattern of family history and age of individual at-risk.

Family history of breast cancer as a risk factor for ovarian cancer in a prospective study

BACKGROUND

A family history of breast cancer has been associated with increased ovarian cancer risk. However, few studies have assessed risk according to characteristics that suggest an inherited cancer susceptibility disorder, such as earlier-than-usual age at cancer diagnosis, family members with double primary cancers of different types, multiple relatives with cancer, and cancer in both members of paired organs.

METHODS

Ovarian cancer risk was assessed according to a detailed breast cancer family history among 49,975 participants in the Breast Cancer Detection Demonstration Project Breast Cancer Defection Demenstration Project (BCDDP) Follow-up Study (1979-1998). In all, 362 incident ovarian cancers were identified during follow-up and rate ratios (RRs) were calculated by Poisson regression. RESULTS.: Breast cancer in a first- or second-degree relative was associated with increased risk of ovarian cancer (RR = 1.4; 95% confidence interval [CI] = 1.1-1.7). Having 2 or more affected first-degree relatives was associated with increased risk (RR = 1.8; 95% CI = 1.1-2.8), especially for women diagnosed with ovarian cancer before age 60 (RR = 4.2; 95% CI = 1.9-9.2) or with a personal history of breast cancer (RR = 3.7; 95% CI 1.8-7.7). Risk was also particularly high for women with 2 or more first-degree relatives with breast cancer and at least 1 affected relative diagnosed before age 50 (RR = 2.6; 95% CI = 1.4-4.8) or with bilateral breast cancer (RR = 4.2; 95% CI = 1.7-10).

CONCLUSIONS

A detailed breast cancer family history as well as an individual's age and personal history of breast cancer are useful for identifying women at elevated genetic risk of ovarian cancer.

Endometrial cancer: Population attributable risks from reproductive, familial and socioeconomic factors

In this study, based on the Swedish Family-Cancer Database, risk factors and their population attributable fractions (PAFs) for endometrial cancer were studied. Over 700,000 women at ages 51-68 years, accumulating 23 million person-years at risk, were entered into Poisson analysis. Overall, reproductive factors (parity and age at last birth) showed a relative risk (RR) of 1.91 and a PAF of 45.51% when the reference group was women with a parity of 3+ and the last childbirth at ages over 34 years. The RR for family history was 2.33 but the PAF was only 2.09%. The RR for socioeconomic factors was a modest 1.12 but the PAF was 6.34%. The combined PAF of these three types of risk factors was 51.84%. Although the present analysis lacked data on some important risk factors for endometrial cancer, the results suggest that a large proportion of the etiology of endometrial cancer can be defined by known epidemiological risk factors.

Cancer risk assessment: quality and impact of the family history interview

BACKGROUND

Identification of individuals at high risk for colon and breast cancer requires an adequate family history assessment and can influence cancer screening and genetic testing decisions. Little data exist that evaluate the completeness of the family history interview in primary care.

METHODS

Retrospective chart review of 995 new patient visits to 28 primary care physicians evaluating the completeness of the family cancer history for colon or breast cancer. Family history information was evaluated for inclusion of age at diagnosis, degree of kinship, and specification of disease of interest.

RESULTS

Family history information on cancer diagnoses was collected on 679 (68%) of the patients. Specific information regarding the individual affected and the cancer diagnosis was present in 414 (61%) of the records. Affected first-degree relatives were more likely to have their age of cancer diagnosis recorded than second-degree relatives (39%, 95% confidence interval [CI]=34%-44% vs 16%, 95% CI=12%-20%). Age at diagnosis of cancer in first-degree relatives was documented in 51% of colon cancers, 38% of breast cancers, and 27% of ovarian cancers. Only 17% of individuals who meet criteria for early-onset breast cancer genetic testing were referred for genetic services.

CONCLUSIONS

Adequate cancer risk assessment using family history information requires age at cancer diagnosis and specification of a cancer diagnosis. Age at diagnosis was frequently missing from family history assessments, which could have a potential impact on identification of high-risk individuals. When family history information does identify high-risk individuals, only the minority are referred for genetic services.

BRCA1 and BRCA2 founder mutations and the risk of colorectal cancer

BACKGROUND

Mutations in BRCA1 and/or BRCA2 (BRCA1/2) profoundly increase the risks of breast and ovarian cancers, but it is unclear whether mutations in these genes increase the risk of colorectal cancer. We investigated BRCA1/2 founder mutations and a family history of breast cancer as potential risk factors for colorectal cancer.

METHODS

In the population-based Molecular Epidemiology of Colorectal Cancer study in northern Israel, 1422 case patients with incident colorectal cancer, diagnosed between March 31, 1998, and December 31, 2002, and 1566 control subjects without colorectal cancer were genotyped for the BRCA1 187delAG, BRCA1 5385insC, and BRCA2 6174delT founder mutations. Genotypes and interview data from all case patients and control subjects and from only those of Ashkenazi Jewish descent (1002 case patients and 1038 control subjects) were used to calculate odds ratios [ORs] from logistic regression.

RESULTS

Twenty-four (2.4%) case patients and 20 (1.9%) control subjects carried one of the three mutations (OR = 1.24, 95% confidence interval [CI] = 0.68 to 2.26). A family history of breast cancer in a female relative was not associated with an increased risk of colorectal cancer, even after adjustment for the presence of a BRCA founder mutation (OR = 1.03, 95% CI = 0.75 to 1.41).

CONCLUSIONS

Although weak associations cannot be excluded, Ashkenazi BRCA founder mutations do not confer a strongly elevated risk of colorectal cancer. Similarly, a family history of breast cancer does not appear to be a strong risk factor for colorectal cancer in this population.

The role of DNA testing in breast, ovarian, and colon cancers

A proportion of cases of breast and colon cancers are caused by inherited mutations that confer a greatly increased susceptibility to malignancy. Certain clinical features may help distinguish patients with a genetic cause for their cancer from the larger number of patients with sporadic tumors. A thorough family medical history is also necessary to identify those at high risk for developing cancer. Many of the normal functions of these genes are understood, and mutation analysis for patients and their families is now available as a clinical service. Presymptomatic detection of mutations allows the patient to pursue preventive measures to reduce the probability of developing a malignancy. Evidence is now available that some prophylactic measures do reduce the incidence of cancer and reduce mortality in mutation carriers, and the standard of care is evolving rapidly. The essential elements necessary to provide accurate interpretations of molecular genetics test results to patients are described.

Family history of colon cancer: what does it mean and how is it useful?

BACKGROUND

Family history of colon cancer can be deconstructed into causal and noncausal explanations, which include genetic factors, environmental factors, gene-environment interactions, misclassification, and differences in screening.

METHODS

We investigated some of these causal and noncausal explanations by using data from a case-control study of colon cancer conducted among African Americans and whites in North Carolina. We examined the relationship between family history and polymorphisms in four genes (N-acetyltransferase 1 and 2 [NAT1, NAT2], methylenetetrahydrofolate reductase, and peroxisome proliferator-activated receptor gamma [PPARG]), environmental risk factors, the joint distributions of these genes and environmental risk factors, and the prevalence of colon cancer screening.

RESULTS

Participants with one or more first-degree relatives with colon cancer showed a slightly higher prevalence of at-risk genotypes for each locus, but results were statistically significant only for NAT2. Participants with a family history showed a higher prevalence of at-risk combinations of genotypes and environmental risk factors (NAT2 and well-done red meat consumption; PPARG and nonsteroidal anti-inflammatory medication use). The sensitivity and predictive value of family history for identifying persons with at-risk genotypes or environmental risk factors was low. History of cancer screening was similar in those with and without a family history.

CONCLUSIONS

Our results suggest that family history of colon cancer may represent aggregation of some genetic polymorphisms and environmental risk factors. Although it is premature to use family history as a screening tool when testing for genetic polymorphisms, further research is needed to identify additional genes and environmental factors that may be associated with family history.

Report of 16 kindreds and one kindred with hMLH1 germline mutation

AIM: To analyze the diagnosis and treatment of 16 hereditary nonpolyposis colorectal cancer (HNPCC) kindreds, and to report the first kindred with hMLH1 germline mutation in Mainland China.

METHODS: The diagnosis, treatment and follow-up study of 16 HNPCC kindreds were retrospectively reviewed. Data concerning site of the malignant tumor, age at the diagnosis, history of synchronous and/or metachronous cancer, and histopathology of tumors were recorded. All treatments had won formal consent. PCR and SSCP were used to screen the coding region of hMLH1 and hMSH2 genes. Variant bands were sequenced by a 377 DNA sequencer.

RESULTS: Among sixteen kindreds, sixty-eight patients had a mean age of 50.8 years, including twenty-one multiple cancer patients and forty-six colorectal cancer patients (metachronous colorectal cancers in sixteen). A total of one hundred and one malignant neoplasms were found in these sixty-eight patients, including 50 colonic, 17 rectal, 11 gastric, 7 endometrial, and 4 esophageal cancers. 39.5% colorectal patients had metachronous cancers within ten years who needed reoperations. A germline G265T nonsense mutation was found in the third exon of hMLH1, resulting in a stop codon and truncated protein. Three phenotypically normal family members were also found to carry the mutated gene.

CONCLUSION: HNPCC is a typical auto-dominant hereditary disease, the main characteristics include early onset and frequency of cancers; predominance of colorectal, especially right-sided colon cancers; frequency of multiple primary cancers (especially colorectal cancers). Segmental resection for colorectal cancers is not eligible for colorectal cancer patient in HNPCC kindreds. Intensive follow-up is essential for all patients and possible gene carriers. The first HNPCC kindred with hMLH1 gene germline mutation was identified in Mainland China, and three phenotypically normal family members were found to be carriers of the mutated gene. The G265T germline (nonsense) mutation in the third exon of hMLH1 found here had not been reported previously in the literature.

Hereditary nonpolyposis colorectal cancer in 95 families: differences and similarities between mutation-positive and mutation-negative kindreds

Hereditary nonpolyposis colorectal cancer (HNPCC) describes the condition of a disparate group of families that have in common a predisposition to colorectal cancer in the absence of a premalignant phenotype. The genetic basis of this disease has been linked to mutations in genes associated with DNA mismatch repair. A large proportion of families harbor changes in one of two genes, hMSH2 and hMLH1. Approximately 35% of families in which the diagnosis is based on the Amsterdam criteria do not appear to harbor mutations in DNA-mismatch-repair genes. In this report we present data from a large series of families with HNPCC and indicate that there are subtle differences between families that harbor germline changes in hMSH2 and families that harbor hMLH1 mutations. Furthermore, there are differences between the mutation-positive group (hMSH2 and hMLH1 combined) of families and the mutation-negative group of families. The major findings identified in this study focus primarily on the extracolonic disease profile observed between the mutation-positive families and the mutation-negative families. Breast cancer was not significantly overrepresented in the hMSH2 mutation-positive group but was overrepresented in the hMLH1 mutation-positive group and in the mutation-negative group. Prostate cancer was not overrepresented in the mutation-positive groups but was overrepresented in the mutation-negative group. In age at diagnosis of colorectal cancer, there was no difference between the hMSH2 mutation-positive group and the hMLH1 mutation-positive group, but there was a significant difference between these two groups and the mutation-negative group.

Increased cancer risk among relatives of nonsmoking lung cancer cases

Lung cancer has been shown to aggregate in families of nonsmoking lung cancer cases with an earlier age at onset. The current study evaluates whether relatives of nonsmoking lung cancer cases are at increased risk of cancers at sites other than lung. Families were identified through 257 population-based, nonsmoking lung cancer cases and 277 population-based, nonsmoking controls residing in metropolitan Detroit. Data were collected for 2,252 relatives of cases and 2,408 relatives of controls. First-degree relatives of nonsmoking lung cancer cases were at 1.52-fold (95% CI, 1.02-2.27) increased risk of cancer of the digestive system after adjustment for each relative's age, race, sex, and smoking status. Relative risk estimates also were elevated, but not significantly, for tobacco-related cancers (RR = 1.39) and breast cancer (RR = 1.72). Among first-degree relatives of younger probands (age 40-59), risk was non-significantly increased 72% (95% CI 0.95-3.10) for all cancers combined and 3.14-fold for cancers of the digestive system (95% CI 0.76-12.9). Nonsmoking relatives of cases were at increased risk of all cancer sites combined (RR = 1.32; 95% CI 1.003-1.73), cancers other than lung (RR = 1.37; 95% CI 1.03-1.82), and digestive system cancers (RR = 2.01; 95% CI 1.20-3.37). These findings of moderate familial aggregation for cancers of the lung, digestive system, breast, and tobacco-related sites suggest that common susceptibility genes may act to increase risk for a variety of cancers in families.

Male breast cancer in the hereditary nonpolyposis colorectal cancer syndrome

A male member of a large HNPCC kindred, affected by primary malignancies of the breast and colon, was identified. This individual was found to harbor a germline mutation of the MLH1 mismatch repair gene previously shown to segregate with disease in this kindred. The breast tumor exhibited somatic reduction to homozygosity for the MLH1 mutation, and microsatellite instability was evident in the breast tumor. We conclude that hereditary male breast cancer can occur as an integral tumor in the HNPCC syndrome.

The utility of pretreatment barium enema in women with endometrial carcinoma

OBJECTIVE

The objective of this study was to assess the clinical utility of a pretreatment barium enema in women with endometrial cancer.

METHODS

The medical records of 249 patients with endometrial cancer who underwent a pretreatment barium enema were retrospectively reviewed. The patients' charts were abstracted for demographic information, stage, grade, histology, current disease status, and barium enema results.

RESULTS

The pretreatment barium enema was normal in 122 (49%) patients. Diverticulosis was the most common abnormality, reported in 112 (45%) patients. Apparent intraluminal abnormalities were found in 15 (6.0%) patients. Each of these patients underwent colonoscopy prior to treatment for endometrial carcinoma. During colonoscopy, benign colonic polyps were removed from 11 (4.4%) patients. Primary colonic adenocarcinoma was discovered in polypoid lesions removed from 2 (0.8%) patients. Significant luminal narrowing from extrinsic lesions was noted in 2 (0.8%) patients, one at the rectosigmoid and the other at the cecum. No patient was found to have colonic mucosal involvement by endometrial cancer.

CONCLUSION

The results of this study do not justify routine pretreatment barium enema to assess the colonic mucosa for metastatic involvement by endometrial cancer or as a screening tool for colorectal cancer in women with endometrial cancer.

Increased incidence of cancer in first degree relatives of women with double primary carcinomas of the breast and colon

Breast and colon cancer are among the most common cancers in the developed world. Several epidemiological studies suggest that the occurrence of one of these two cancers in a woman may predispose to the development of the other. The occurrence of both forms of cancer in the same woman may be because of chance or common susceptibility. In order to determine how frequently double primary cancers have a hereditary basis, we conducted a registry based study at a single Montreal hospital. Cancer rates in first degree relatives of patients with multiple primaries were compared with provincial age standardised incidence rates and relative risks (RRs) were estimated. In first degree relatives under 45 there was a total of 15 cancers observed, compared with 3.70 expected, giving an RR of 4.05 (95% CI: 2.27-6.68). The RR for colon cancer was significantly increased among male relatives. For relatives less than 45 years old at diagnosis, the RR for colon cancer was 66.7 (95% CI: 13.8-195) (three cases observed, 0.045 expected). For all ages the RR was 5.02 (95% CI: 2.04-10.5). The RR for breast cancer was 5.92 (95% CI: 1.91-13.8) for female relatives under 45 (five cases observed, 0.845 expected) and 2.14 (95% CI: 1.07-3.83) for breast cancer at any age. These results suggest that there may be genes that predispose to both breast and colon cancer in certain people.

Molecular genetic evidence of the occurrence of breast cancer as an integral tumor in patients with the hereditary nonpolyposis colorectal carcinoma syndrome

BACKGROUND

The hereditary nonpolyposis colorectal carcinoma (HNPCC) syndrome is an autosomal dominant genetic disorder caused by the inheritance of a mutation in one of a family of genes encoding DNA mismatch repair (MMR) proteins. HNPCC manifests as genetic instability in linked tumors. Clinically, the syndrome is characterized by early onset malignancies, primarily of the colon and endometrium, with an increased incidence of tumors at other gastrointestinal sites, upper urologic tract, ovary, and pancreas as well. However, the inclusion of breast cancer as an integral tumor of this syndrome is controversial.

METHODS

Mutation screening of MMR genes was carried out by single strand conformation polymorphism (SSCP) and sequencing analyses of genomic DNA prepared from normal lymphocytes. Expression analysis was performed by SSCP. Sequence analyses of cDNA was prepared from breast tumor tissue and normal lymphocytes. Genetic instability was assessed by comparing the electrophoretic mobility of polymerase chain reaction (PCR) products using multiple microsatellite markers.

RESULTS

A 4-bp frameshift mutation in the hMLH1 gene was found to segregate with disease in the germlines of the affected members of a large kindred HNPCC. Expression of only the mutant allele was observed in the breast cancer tissue of one family member, however both alleles were observed in her normal tissue. This breast cancer exhibited widespread microsatellite instability, as did breast cancers obtained from several other HNPCC kindreds.

CONCLUSIONS

These data indicate that breast cancer may result from the inheritance of a mutant MMR gene, and that breast cancer may occur as an integral tumor in the HNPCC syndrome.

Familial breast cancer

Tremendous progress has been made in recent years in understanding the genetic basis of breast cancer. Epidemiological models have been devised which allow risk estimation for women with one or two relatives with breast cancer. The existence of two autosomal dominant breast cancer susceptibility genes (BRCA1 and BRCA2) have been documented. BRCA1 has been isolated and we are beginning to catalog BRCA1 mutations which appear to be etiologically related to the development of breast cancer in certain families. These BRCA1 mutation studies and the isolation of BRCA2 will allow development of accurate DNA-based testing for the prediction of individual risk in women with a family history of breast cancer. Work by several groups is progressing rapidly on the isolation BRCA2. Ongoing studies investigating the function of BRCA1, and eventually BRCA2, will lead to a better understanding of the role these important genes normally play in preventing the development of breast cancer. Finally, additional breast cancer susceptibility genes are likely to be identified, further expanding the number of tools we have to study, and eventually prevent, breast cancer.

Validation of family history of breast cancer and identification of the BRCA1 and other syndromes using a population-based cancer registry

A major risk factor for breast cancer is family history of the disease in first-degree relatives. This study evaluates the validity of family history information on breast cancer in mothers and sisters of breast cancer probands from the cancer registry (CR) compared to personal interviews (PI) of 359 consecutive population-based cases of breast cancer. Breast cancer is seen in mothers of 14% of probands by CR compared to 12% by PI. Further, 13% of probands have a sister with breast cancer using CR compared to 12% by PI. Using PI as the standard, the sensitivity of the CR family history data in mothers is 92% and the specificity is 99%, while in sisters they are 88% and 99%, respectively. These estimates were calculated on cases where family history information is available in the CR. Sensitivity and specificity are recalculated, recording an "error" whenever family history information is not available, and they are 75% and 68%, respectively, for mothers and 72% and 70%, respectively, for sisters. Estimates of proband-mother and proband-sisters familial breast cancer from CR and PI are sufficiently similar to warrant the use of CR family history data in studies of genetic epidemiology. The family phenotype consistent with the BRCA1 syndrome was found in four (1.1%) probands, all below age 50 years, while for BRCA2 there were five (1.4%) probands, three below age 50 years and two 50 years or older. Site-specific familial breast cancer was found in 23 (6.4%) probands. Population-based multiple-case breast cancer families can rapidly be identified through CR. These families can make substantial contributions to the study of genetic and environmental etiology of the disease as well as benefit from preventive and therapeutic efforts. As new knowledge and tools in molecular genetics become available, there is an urgent need for large population-based registries of families at high risk for cancer.

Risks of cancer among members of families in the Gilda Radner Familial Ovarian Cancer Registry

BACKGROUND

Increasing scientific and public interest in hereditary cancer syndromes has created a need for estimates of lifetime cancer risks among members of families with such syndromes.

METHODS

Data from the Gilda Radner Familial Ovarian Cancer Registry were used to evaluate risk for cancers of the breast, cervix, uterus, colorectum, and prostate in members of 143 families containing three or more reported cases of ovarian cancer among first- or second-degree relatives. These risks were compared with those that were expected based on general population rates obtained from the Connecticut Tumor Registry.

RESULTS

Overall, family members' risk of cancer at any nonovarian site was 1.5 times that of the general population (P < 0.001). Among female members, risk for cancer of the breast was 2.5 times that of the general population. Risk for cancer of the uterus was 5 times that of the general population and increased with increasing number of first-degree relatives with ovarian cancer. Among male family members having three or more first-degree relatives with ovarian cancer, prostate cancer risk was 4.5 times that of the general population. No excess risks were observed for cancer of the colorectum.

CONCLUSIONS

These data support previous reports of coaggregation of cancer of the breast, uterus and ovary, and suggest coaggregation between cancer of the ovary and prostate. Differences in cancer risk profiles observed in these families with multiple ovarian cancer and in carriers of the gene BRCA1 suggest that hereditary ovarian cancer is genetically heterogeneous.

Etiology, biology, and epidemiology of ovarian cancer

Epithelial ovarian cancer kills more women per year than all other gynecologic cancers combined. Pregnancy, oral contraceptive use, and tubal ligation decrease the risk of the disease, whereas risk is increased for women whose family history is consistent with one of the familial ovarian cancer syndromes. Several theories have been postulated concerning the etiology of ovarian cancer, including the incessant ovulation theory and that based on the model of hypergonadotropic hypogonadism. Chromosomal abnormalities and allele losses have been described in ovarian cancers. Involvement of oncogenes and tumor suppressor genes has been investigated as well. Genetic linkage studies are ongoing in families whose history is consistent with one of the familial ovarian cancer syndromes.