The risk of breast cancer in BRCA1 and BRCA2 mutation carriers without a first-degree relative with breast cancer.

The objective of this study was to estimate the lifetime risk of breast cancer in women with a BRCA1 or BRCA2 mutation with and without at least 1 first-degree relative with breast cancer. A total of 2835 women with a BRCA1 or BRCA2 mutation were followed. Age- and gene-specific breast cancer rates were calculated. The relative risks of breast cancer for subjects with a family history of breast cancer, compared to no family history were calculated. The mean age at baseline was 41.1 years, and they were followed for a mean of 6.0 years. The estimated penetrance of breast cancer to age 80 years was 60.8% for BRCA1 and 63.1% for BRCA2. For all BRCA carriers, the penetrance of breast cancer to age 80 for those with no first-degree relative with breast cancer was 60.4% and 63.3% for those with at least 1 first-degree relative with breast cancer. The risk of breast cancer for BRCA carriers with no first-degree relative with breast cancer is substantial, and as a result, clinical management for these women should be the same as those for women with an affected relative.

Lynch syndrome in the 21st century: clinical perspectives.

Lynch syndrome (LS) is the most common of all inherited cancer syndromes, associated with substantially elevated risks for colonic and extracolonic malignancies, earlier onset and high rates of multiple primary cancers. At the genetic level, it is caused by a defective mismatch repair (MMR) system due to presence of germline defects in at least one of the MMR genes- MLH1, MSH2, MSH6, PMS2 or EPCAM. An impaired MMR function during replication introduces infidelity in DNA sequence and leads to ubiquitous mutations at simple repetitive sequences (microsatellites), causing microsatellite instability (MSI). Although previously, clinicopathological criteria such as Amsterdam I/II and Revised Bethesda Guidelines were commonly used to identify suspected LS mutation carriers, there has been a recent push towards universally testing, especially in case of colorectal cancers (CRCs), through immunohistochemistry for expression of MMR proteins or through molecular tests (polymerase chain reaction, PCR) for MSI, in order to identify LS mutation carriers and subject them to genetic testing to ascertain the specific gene implicated. In this review, we have discussed the latest diagnostic strategies and the current screening and treatment guidelines for colonic and extracolonic cancers in clinically affected and at-risk individuals for LS.

Prevalence of PALB2 mutations in the Creighton University Breast Cancer Family Registry.

The purpose of this study is to determine the prevalence of PALB2 mutations among breast cancer families from the United States. The PALB2 gene was screened for mutations in 90 familial breast cancer patients from the Creighton University Breast Cancer Family Registry. These patients had previously tested negative for mutations in BRCA1 and BRCA2. Two of 90 breast cancer patients (2.2 %) were found to carry a truncating mutation in PALB2 (c.2411_2412delCT and c.2053delC). Both probands were diagnosed with breast cancer before age 35 and each had three relatives with breast cancer. Mutations in PALB2 are less common than BRCA1 and BRCA2 in familial breast cancer patients. However, testing for PALB2 mutations is a useful adjunct for patients undergoing testing for BRCA1 and BRCA2.

A prior diagnosis of breast cancer is a risk factor for breast cancer in BRCA1 and BRCA2 carriers.

BACKGROUND: The risk of breast cancer in carriers of BRCA1 and BRCA2 mutations is influenced by factors other than the genetic mutation itself. Modifying factors include a woman's reproductive history and family history of cancer. Risk factors are more likely to be present in women with breast cancer than in women without breast cancer, and therefore the risk of cancer in the two breasts should not be independent. It is not clear to what extent modifying factors influence the risk of a first primary or a contralateral breast cancer in BRCA carriers. METHODS: We conducted a matched case-control study of breast cancer among 3920 BRCA1 or BRCA2 mutation carriers. We asked whether a past history of breast cancer in the contralateral breast was a risk factor for breast cancer. RESULTS: After adjustment for age, country of residence, and cancer treatment, a previous cancer of the right breast was found to be a significant risk factor for cancer of the left breast among BRCA1 or BRCA2 carriers (relative risk: 2.1; 95% confidence interval: 1.4 to 3.0; p < 0.0001). CONCLUSIONS: In a woman with a BRCA1 or BRCA2 mutation who is diagnosed with breast cancer, the risk of cancer in the contralateral breast depends on the first diagnosis. That observation supports the hypothesis that there are important genetic or non-genetic modifiers of cancer risk in BRCA carriers. Discovering risk modifiers might lead to greater personalization of risk assessment and management recommendations for BRCA-positive patients.

Inherited genetic susceptibility to multiple myeloma.

Although the familial clustering of multiple myeloma (MM) supports the role of inherited susceptibility, only recently has direct evidence for genetic predisposition been demonstrated. A meta-analysis of two genome-wide association (GWA) studies has identified single-nucleotide polymorphisms (SNPs) localising to a number of genomic regions that are robustly associated with MM risk. In this review, we provide an overview of the evidence supporting a genetic contribution to the predisposition to MM and MGUS (monoclonal gammopathy of unknown significance), and the insight this gives into the biological basis of disease aetiology. We also highlight the promise of future approaches to identify further specific risk factors and their potential clinical utility.

Communication and technology in genetic counseling for familial cancer.

When a cancer predisposing germline mutation is detected in an index case, the presence of the underlying syndrome is confirmed and the potential for predictive testing of at-risk relatives is established. However, the reporting of a positive family history does not routinely lead to communication of information about risk to close, much less distant relatives. This review summarizes information technology utilized to address penetration or 'reach' of knowledge of risk within extended families, including the use of telephone and video counseling to reach distant patients, and anticipate novel internet-based processes for communication between investigators and relatives.

Incidence of colorectal cancer in BRCA1 and BRCA2 mutation carriers: results from a follow-up study.

BACKGROUND: The BRCA1 and BRCA2 genes confer increased susceptibility to breast and ovarian cancer and to a spectrum of other cancers. There is controversy regarding the risk of colorectal cancer conferred by germline mutations in these two genes. METHODS: We followed 7015 women with a BRCA mutation for new cases of colorectal cancer. Incidence rates in carriers were compared with population-specific incidence rates, and standardised incidence ratios (SIRs) were estimated. The expected numbers of cancers were computed by multiplying person-years at risk by the appropriate age-, sex- and country-specific incidence rates from the five countries. RESULTS: Twenty-one incident colorectal cancer cases were observed among all mutation carriers, compared with 23.6 cases expected. The SIR for BRCA1 carriers was 0.92 (95% confidence interval (CI), 0.54-1.40, P=0.7) and for BRCA2 carriers was 0.82 (95% CI, 0.30-1.81, P=0.7). The SIR for colon cancer was 3.81 (95% CI 1.77-7.23) for women below the age of 50 years (both genes combined) and was 0.60 (95% CI 0.33-1.00) for women aged 50 years and above. CONCLUSION: The risk of colorectal cancer is increased in female carriers of BRCA1 mutations below the age of 50 years but not in women with BRCA2 mutations or in older women.

Hereditary ovarian and breast cancer: what have we learned?

An autosomal-dominant inherited trait predisposing women to both breast cancer (BC) and ovarian cancer (OC) was first described in 1971. Subsequent strides were made in identifying mutations in the eventually cloned genes BRCA1 and BRCA2 as being responsible for hereditary BC and OC (HBOC) in many women with early-onset HBOC. More recently, modifiers of BC risk have also been identified and are under study. The biological and molecular genetic pathways for malignant transformation in OC (ovarian epithelium and/or epithelium of the fallopian tube or, possibly, the endometrium and endocervix) remain elusive. The answer to the question 'What have we learned?' which is part of our chapter title unfortunately remains incomplete. However, intensive worldwide research indicates that its malignant transformation is the product of a multi-step process where there is an array of mutations which account for three or more classes of genes, inclusive of proto-oncogenes, tumor suppressor genes and mutator genes. This causal uncertainty heralds an enormous clinical-pathology dilemma, given the fact that epithelial OC, together with related Müllerian duct carcinoma, harbor the highest fatality rates of all gynecologic malignancies.

The incidence of pancreatic cancer in BRCA1 and BRCA2 mutation carriers.

BACKGROUND: Germline mutations in BRCA1 and BRCA2 predispose to pancreatic cancer. We estimated the incidence of pancreatic cancer in a cohort of female carriers of BRCA1 and BRCA2 mutation. We also estimated survival rates in pancreatic cancer cases from families with a BRCA mutation. METHODS: We followed 5149 women with a mutation for new cases of pancreatic cancer. The standardised incidence ratios (SIR) for pancreatic cancer were calculated based on age group and country of residence. We also reviewed the pedigrees of 8140 pedigrees with a BRCA1 or a BRCA2 mutation for those with a case of pancreatic cancer. We recorded the year of diagnosis and the year of death for 351 identified cases. RESULTS: Eight incident pancreatic cancer cases were identified among all mutation carriers. The SIR for BRCA1 carriers was 2.55 (95% CI=1.03-5.31, P=0.04) and for BRCA2 carriers was 2.13 (95% CI=0.36-7.03, P=0.3). The 5-year survival rate was 5% for cases from a BRCA1 family and 4% for cases from a BRCA2 family. CONCLUSION: The risk of pancreatic cancer is approximately doubled in female BRCA carriers. The poor survival in familial pancreatic cancer underscores the need for novel anti-tumoural strategies.

Predictors of contralateral breast cancer in BRCA1 and BRCA2 mutation carriers.

PURPOSE: The objective of this study was to estimate the risk of contralateral breast cancer in BRCA1 and BRCA2 carriers; and measure the extent to which host, family history, and cancer treatment-related factors modify the risk. PATIENTS AND METHODS: Patients were 810 women, with stage I or II breast cancer, for whom a BRCA1 or BRCA2 mutation had been identified in the family. Patients were followed from the initial diagnosis of cancer until contralateral mastectomy, contralateral breast cancer, death, or last follow-up. RESULTS: Overall, 149 subjects (18.4%) developed a contralateral breast cancer. The 15-year actuarial risk of contralateral breast cancer was 36.1% for women with a BRCA1 mutation and was 28.5% for women with a BRCA2 mutation. Women younger than 50 years of age at the time of breast cancer diagnosis were significantly more likely to develop a contralateral breast cancer at 15 years, compared with those older than 50 years (37.6 vs 16.8%; P=0.003). Women aged <50 years with two or more first-degree relatives with early-onset breast cancer were at high risk of contralateral breast cancer, compared with women with fewer, or no first-degree relatives with breast cancer (50 vs 36%; P=0.005). The risk of contralateral breast cancer was reduced with oophorectomy (RR 0.47; 95% CI 0.30-0.76; P=0.002). CONCLUSION: The risk of contralateral breast cancer risk in BRCA mutation carriers declines with the age of diagnosis and increases with the number of first-degree relatives affected with breast cancer. Oophorectomy reduces the risk of contralateral breast cancer in young women with a BRCA mutation.

Review of the Lynch syndrome: history, molecular genetics, screening, differential diagnosis, and medicolegal ramifications.

More than one million patients will manifest colorectal cancer (CRC) this year of which, conservatively, approximately 3% (approximately 30,700 cases) will have Lynch syndrome (LS), the most common hereditary CRC predisposing syndrome. Each case belongs to a family with clinical needs that require genetic counseling, DNA testing for mismatch repair genes (most frequently MLH1 or MSH2) and screening for CRC. Colonoscopy is mandated, given CRC's proximal occurrence (70-80% proximal to the splenic flexure). Due to its early age of onset (average 45 years of age), colonoscopy needs to start by age 25, and because of its accelerated carcinogenesis, it should be repeated every 1 to 2 years through age 40 and then annually thereafter. Should CRC occur, subtotal colectomy may be necessary, given the marked frequency of synchronous and metachronous CRC. Because 40-60% of female patients will manifest endometrial cancer, tailored management is essential. Additional extracolonic cancers include ovary, stomach, small bowel, pancreas, hepatobiliary tract, upper uroepithelial tract, brain (Turcot variant) and sebaceous adenomas/carcinomas (Muir-Torre variant). LS explains only 10-25% of familial CRC.

Rapid progression of prostate cancer in men with a BRCA2 mutation.

Men with BRCA2 mutations have been found to be at increased risk of developing prostate cancer. There is a recent report that BRCA2 carriers with prostate cancer have poorer survival than noncarrier prostate cancer patients. In this study, we compared survival of men with a BRCA2 mutation and prostate cancer with that of men with a BRCA1 mutation and prostate cancer. We obtained the age at diagnosis, age at death or current age from 182 men with prostate cancer from families with a BRCA2 mutation and from 119 men with prostate cancer from families with a BRCA1 mutation. The median survival from diagnosis was 4.0 years for men with a BRCA2 mutation vs 8.0 years for men with a BRCA1 mutation, and the difference was highly significant (P<0.01). It may be important to develop targeted chemotherapies to treat prostate cancer in men with a BRCA2 mutation.

Ratio of male to female births in the offspring of BRCA1 and BRCA2 carriers.

A recent report based on 68 families, including 17 with mutations in BRCA1, suggested that there was an excess of female offspring born to BRCA1 mutation carriers. We have examined the gender ratio among offspring of 511 mutation carriers from 116 BRCA1 families, 77 and 39 from Australia and the United States, respectively. We found no evidence for a significant deviation from the expected proportion of female offspring in the Australian pedigrees, but there was an excess of female offspring in pedigrees from the USA. Ascertainment bias probably explains this bias, rather than a link with X-chromosome inactivation as previously suggested, because the families from the USA were ascertained for the purposes of linkage studies whereas those from Australia were ascertained through Familial Cancer Clinics to which they had been referred for clinical genetic counseling and mutation testing.

Breast-feeding and the risk of breast cancer in BRCA1 and BRCA2 mutation carriers.

BACKGROUND: Several studies have reported that the risk of breast cancer decreases with increasing duration of breast-feeding. Whether breast-feeding is associated with a reduced risk of hereditary breast cancer in women who carry deleterious BRCA1 and BRCA2 mutations is currently unknown. METHODS: We conducted a case-control study of women with deleterious mutations in either the BRCA1 or the BRCA2 gene. Study participants, drawn from an international cohort, were matched on the basis of BRCA mutation (BRCA1 [n = 685] or BRCA2 [n = 280]), year of birth (+/-2 years), and country of residence. The study involved 965 case subjects diagnosed with breast cancer and 965 control subjects who had no history of breast or ovarian cancer. Information on pregnancies and breast-feeding practices was derived from a questionnaire administered to the women during the course of genetic counseling. Conditional logistic regression analyses were used to estimate odds ratios (ORs) for the risk of breast cancer. All statistical tests were two-sided. RESULTS: Among women with BRCA1 mutations, the mean total duration of breast-feeding was statistically significantly shorter for case subjects than for control subjects (6.0 versus 8.7 months, respectively; mean difference = 2.7 months, 95% confidence interval [CI] = 1.4 to 4.0; P<.001). The total duration of breast-feeding was associated with a reduced risk of breast cancer (for each month of breast-feeding, OR = 0.98, 95% CI = 0.97 to 0.99; P(trend)<.001). Women with BRCA1 mutations who breast-fed for more than 1 year were less likely to have breast cancer than those who never breast-fed (OR = 0.55, 95% CI = 0.38 to 0.80; P =.001), although no such association was seen for BRCA2 (OR = 0.95, 95% CI = 0.56 to 1.59; P =.83). CONCLUSIONS: Women with deleterious BRCA1 mutations who breast-fed for a cumulative total of more than 1 year had a statistically significantly reduced risk of breast cancer.

The prevalence of MADH4 and BMPR1A mutations in juvenile polyposis and absence of BMPR2, BMPR1B, and ACVR1 mutations.

BACKGROUND: Juvenile polyposis (JP) is an autosomal dominant syndrome predisposing to colorectal and gastric cancer. We have identified mutations in two genes causing JP, MADH4 and bone morphogenetic protein receptor 1A (BMPR1A): both are involved in bone morphogenetic protein (BMP) mediated signalling and are members of the TGF-beta superfamily. This study determined the prevalence of mutations in MADH4 and BMPR1A, as well as three other BMP/activin pathway candidate genes in a large number of JP patients. METHODS: DNA was extracted from the blood of JP patients and used for PCR amplification of each exon of these five genes, using primers flanking each intron-exon boundary. Mutations were determined by comparison to wild type sequences using sequence analysis software. A total of 77 JP cases were sequenced for mutations in the MADH4, BMPR1A, BMPR1B, BMPR2, and/or ACVR1 (activin A receptor) genes. The latter three genes were analysed when MADH4 and BMPR1A sequencing found no mutations. RESULTS: Germline MADH4 mutations were found in 14 cases (18.2%) and BMPR1A mutations in 16 cases (20.8%). No mutations were found in BMPR1B, BMPR2, or ACVR1 in 32 MADH4 and BMPR1A mutation negative cases. DISCUSSION: In the largest series of JP patients reported to date, the prevalence of germline MADH4 and BMPR1A mutations is approximately 20% for each gene. Since mutations were not found in more than half the JP patients, either additional genes predisposing to JP remain to be discovered, or alternate means of inactivation of the two known genes are responsible for these JP cases.

Carrier risk status changes resulting from mutation testing in hereditary non-polyposis colorectal cancer and hereditary breast-ovarian cancer.

CONTEXT: In hereditary cancer syndrome families with an identified cancer associated mutation, mutation testing changes the carrier risk status of the tested person and may change the carrier risk status of relatives. OBJECTIVE: This study aimed to describe the change in the distribution of carrier risk status resulting from testing in hereditary breast-ovarian cancer (HBOC) and hereditary non-polyposis colorectal cancer (HNPCC) families. DESIGN: This was an observational cohort study. PATIENTS: The cohort included members of 75 HBOC and 47 HNPCC families. Of the 10 910 cohort members, 1408 were tested for a mutation and learned their test results. OUTCOME MEASURE: Carrier risk for all cohort members was assessed before and after mutation testing. RESULTS: There was a change in carrier risk status in 2906 subjects after testing of 1408 family members. The most common type of carrier risk change, from at risk to non-carrier status, accounted for 77% of the risk changes; 12% were a change to known carrier status from a lower risk. Sixty percent of persons with a carrier risk status change were not themselves tested; their risk status changed because of a relative's test result. CONCLUSIONS: Carrier risk status changes from uncertainty to certainty (that is, to carrier or to non-carrier) account for 89% of risk changes resulting from testing. These risk changes affect cancer prevention recommendations, most commonly reducing their burden. Current practices do not ensure that untested family members are informed about changes in their carrier risk status which result from mutation testing of their relatives.