Two Swedish founder MSH6 mutations, one nonsense and one missense, conferring high cumulative risk of Lynch syndrome.

Lynch syndrome, or hereditary non-polyposis colorectal cancer (HNPCC), is a cancer susceptibility syndrome caused by germline mutations in mismatch-repair genes, predominantly MLH1, MSH2 and MSH6. A majority of the mutations reported are truncating, but for MSH6, missense mutations constitute over one third. Few have been proven pathogenic in functional studies or shown to segregate in families. In this study, we show segregation of the putative pathogenic MSH6 missense mutation c.1346T>C p.Leu449Pro with microsatellite instability-high Lynch syndrome-related tumours lacking MSH6 expression in a large 17th century pedigree. Another large family with the MSH6 nonsense c.2931C>G, p.Tyr977X mutation is similar in tumour spectra, age of onset and cumulative risk. These MSH6 families, despite their late age of onset, have a high lifetime risk of all Lynch syndrome-related cancers, significantly higher in women (89% by age 80) than in men (69%). The gender differences are in part explained by high endometrial (70%) and ovarian (33%) cancer risks added upon the high colorectal cancer risk (60%). The several occurrences of breast cancer are not due to the MSH6 mutations. These findings are of great importance for counselling, management and surveillance of families with MSH6 mutations.

Hereditary prostate cancer: clinical characteristics and survival.

PURPOSE: Hereditary prostate cancer accounts for 5% to 10% of all prostate cancer cases. We assessed clinical characteristics and survival in patients with hereditary prostate cancer MATERIALS AND METHODS: The study comprised 201 patients from 62 Swedish hereditary prostate cancer families and 402 controls with prostate cancer who were matched for age and calendar year at diagnosis, and the hospital where the diagnosis was made. Clinical data were obtained from the National Cancer Registry, Causes of Death Registry and medical records. RESULTS: Median age at the diagnosis of hereditary prostate cancer was 68 years, which was 6 years less than in patients with prostate cancer in the general population in Sweden. Distributions of tumor grade, symptoms at diagnosis and initial therapy were similar in hereditary prostate cancer cases and controls. More controls were classified with localized disease but it may have been due to methodological problems. Overall and cancer specific survival was similar in patients with hereditary prostate cancer and controls as well as in subgroup analyses including those with early onset and those diagnosed before 1990. Prostate cancer was the cause of death in 75% of patients with hereditary prostate cancer, in contrast to 55% with prostate cancer in the Swedish population. This difference was completely explained by the earlier age at the diagnosis of hereditary prostate cancer. CONCLUSIONS: Hereditary prostate cancer has an earlier onset than sporadic prostate cancer but this study did not indicate any other important difference in clinical characteristics or survival in patients with hereditary prostate cancer and those with sporadic prostate cancer. However, it cannot be excluded that individual hereditary prostate cancer genes may have specific biological characteristics.

A population based cohort study of patients with multiple colon and endometrial cancer: correlation of microsatellite instability (MSI) status, age at diagnosis and cancer risk.

Hereditary non-polyposis colorectal cancer, HNPCC, is an autosomal dominant condition predisposing to cancers of primarily the colorectum and the endometrium. The aim of our study was to identify persons at a high risk of hereditary colorectal cancer and to estimate their risk of colon and other HNPCC-associated tumours. Family histories of cancer were obtained on 89 persons with double primary (DP) cancers of the colon and the endometrium. The cancer risks in their 649 first-degree-relatives (FDR) were analysed. The microsatellite instability (MSI) status of the tumour of the proband was also analysed and the cancer risks were estimated in relation to MSI status and age at diagnosis in the proband (over or under 50 years). The overall standardised incidence ratio (SIR) was 1.69 (95% CI; 1.39-2.03). In the =50-year-old cohort the SIR was 2.67 (95% CI; 2.08-3.38). Colon, rectal and uterus cancer exhibited significantly increased risks. This risk was further increased in the =50-year-old MSI positive families. Several =50-year-old MSI negative HNPCC-like families with increased risks were also identified. In conclusion a FDR to a person with a DP cancer of the colorectum or the colon/endometrium have a significantly increased risk of having a colorectal or other HNPCC-associated cancers if the proband is diagnosed with one of the cancers before age 50. These families are candidates for genetic counselling and colorectal screening programmes. Mutations in mismatch repair genes can explain some of the increased risk in these families, but mutations in MSI negative families are probably due to other colon cancer susceptibility genes not yet described.

BRCA2 mutation in a family with hereditary prostate cancer.

Hereditary prostate cancer is a genetically heterogeneous disease, and so far four different susceptibility loci have been identified. Reports of associated cancers are few, and it is generally considered a site-specific disease. However, some reports have shown an elevated risk for prostate cancer among BRCA2 mutation carriers. In this report, we present a family in which the father and four of his sons were diagnosed with prostate cancer at exceptionally early ages (51, 52, 56, 58, and 63 years, respectively). In addition, three daughters were diagnosed with breast cancer between the ages of 47 and 61. In this family, a truncating mutation in exon 11, 6051delA of the BRCA2 gene, leading to an early termination of the protein (codon 1962), was identified. Although BRCA2 is probably responsible only for a very small fraction of hereditary prostate cancers, this finding supports previous reports of an increased risk of prostate cancer in BRCA2 mutation carriers.

Low frequency of allelic imbalance at the prostate cancer susceptibility loci HPC1 and 1p36 in Swedish men with hereditary prostate cancer.

The aim of this study was to investigate allelic imbalance at the major human prostate cancer susceptibility locus HPC1 at 1q24-25 and the recently reported, putative, susceptibility locus at 1p36 in prostate tumors from Swedish families with hereditary prostate cancer. We analyzed 31 prostate tumors and two lymph node metastases from 33 Swedish men in 22 families with hereditary prostate cancer for the presence of allelic imbalance using microsatellite markers D1S158, D1S422, and D1S238 for the HPC1 locus and D1S1597, D1S407, and D1S489 for the 1p36 locus. Frequencies of allelic imbalance at the two investigated loci were quite low, 3 of 27 informative tumors at the 1p36 locus and 3 of 27 informative tumors at the HPC1 locus. Interestingly, two tumors showed allelic imbalance at both loci investigated, suggesting that they may have lost a great part of chromosome 1. Taking this possibility into consideration, the specific loss of the two investigated loci may be even lower (1 of 27 informative tumors for either locus). The very low level of allelic imbalance found at HPC1 and 1p36 makes it unlikely that these loci encode genes that are acting as classic tumor suppressor genes in the initiation or progression of hereditary prostate cancer. Of the eight tumors from HPC1-linked families, only two showed AI at the HPC1 locus, one of which had lost the wild-type allele.

Cancer risk in families with hereditary prostate carcinoma.

BACKGROUND: Little is known regarding the clinical features of hereditary prostate carcinoma (HPC) and whether other malignancies are associated with this disease. The aim of this study was to investigate whether tumors other than prostate carcinoma aggregate in families with HPC or whether this disease can be considered site specific. METHODS: From 62 Swedish families with HPC, a cohort was constructed of 1364 first-degree relatives of the men with prostate carcinoma in these families. Through linkage to the Swedish Cancer Register, all reported cancer between 1958 and 1996 was identified. The expected number of cases was calculated by using the population rates in Sweden. RESULTS: A standardized incidence ratio (SIR) of 1. 16 (95% confidence interval [95% CI], 0.97-1.38) for the overall cancer risk was observed among the 1364 first-degree relatives. However, significant increased risks were noticed for gastric carcinoma (SIR, 2.78; 95% CI, 1.59-4.52), for breast carcinoma in women (SIR, 1.58; 95% CI, 1.01-2.35), and for kidney carcinoma (SIR, 2.51; 95% CI, 1.15-4.77).The excess risk for breast carcinoma was even more pronounced among women before the age of 65 years in families with earlier onset prostate carcinoma (SIR, 3.64; 95% CI, 1. 66-6.91). Seven families with at least two or more relatives with breast, gastric, or kidney carcinoma were identified, and, in one family, four relatives with early onset gastric carcinoma were observed. CONCLUSIONS: In most of the families with HPC, the disease appears to be "site specific," with no excess of other malignancies. However, in a subset of families, a significant aggregation of prostate carcinoma together with breast carcinoma and/or gastric carcinoma was observed that may have been caused by a common germline mutation in a cancer susceptibility gene.

Risk perception, screening practice and interest in genetic testing among unaffected men in families with hereditary prostate cancer.

Approximately 5-10% of prostate cancer cases are caused by dominantly inherited susceptibility to the disease. Although advances have been made in research concerning the genetic mechanisms of hereditary prostate cancer, little is known about the psychological consequences for men at high risk of developing the disease. The aims of the present study were to examine risk perception, interest in genetic investigations, cancer-specific worry, and screening practice among unaffected men, aged 40-72 years old, with a pedigree consistent with hereditary prostate cancer and an estimated lifetime risk of prostate cancer of 35-45%. A questionnaire was sent by mail to 120 subjects, of whom 110 responded. Most of the men (n = 90, 82%) worried about having an inherited susceptibility to prostate cancer, and 34 (31%) claimed that worry about prostate cancer affected their daily life (3 (3%) fairly much, 31 (28%) slightly). As many as 40% of the study subjects perceived their lifetime risk of prostate cancer as 67% or more. Perceived high risk was associated with symptoms of depression and with cancer worry affecting daily living. Two-thirds of the men aged 50 years old or more were regularly screened for prostate cancer. Subjects with high levels of cancer-specific stress, as measured by the avoidance subscale of the Impact of Event Scale, were less likely to opt for screening. Almost all of the men (94%) were interested in presymptomatic genetic testing (84 (76%) "definitely yes" and 20 (18%) "probably yes"). We conclude that hereditary susceptibility to prostate cancer has significant psychological consequences although it rarely causes psychiatric morbidity. The present study underlines the importance of giving thorough, repeated information to men at high risk of prostate cancer.

In Swedish families with hereditary prostate cancer, linkage to the HPC1 locus on chromosome 1q24-25 is restricted to families with early-onset prostate cancer.

Prostate cancer clusters in some families, and an estimated 5%-10% of all cases are estimated to result from inheritance of prostate cancer-susceptibility genes. We previously reported evidence of linkage to the 1q24-25 region (HPC1) in 91 North American and Swedish families each with multiple cases of prostate cancer (Smith et al. 1996). In the present report we analyze 40 (12 original and 28 newly identified) Swedish families with hereditary prostate cancer (HPC) that, on the basis of 40 markers spanning a 25-cM interval within 1q24-25, have evidence of linkage. In the complete set of families, a maximum two-point LOD score of 1.10 was observed at D1S413 (at a recombination fraction [theta] of.1), with a maximum NPL (nonparametric linkage) Z score of 1.64 at D1S202 (P=.05). The evidence of linkage to this region originated almost exclusively from the subset of 12 early-onset (age <65 years) families, which yielded a maximum LOD score of 2.38 at D1S413 (straight theta=0) and an NPL Z score of 1.95 at D1S422 (P=.03). Estimates from heterogeneity tests suggest that, within Sweden, as many as 50% of early-onset families had evidence of linkage to the HPC1 region. These results are consistent with the hypothesis of linkage to HPC1 in a subset of families with prostate cancer, particularly those with an early age at diagnosis.

Evidence for a prostate cancer susceptibility locus on the X chromosome.

Over 200,000 new prostate cancer cases are diagnosed in the United States each year, accounting for more than 35% of all cancer cases affecting men, and resulting in 40,000 deaths annually. Attempts to characterize genes predisposing to prostate cancer have been hampered by a high phenocopy rate, the late age of onset of the disease and, in the absence of distinguishing clinical features, the inability to stratify patients into subgroups relative to suspected genetic locus heterogeneity. We previously performed a genome-wide search for hereditary prostate cancer (HPC) genes, finding evidence of a prostate cancer susceptibility locus on chromosome 1 (termed HPC1; ref. 2). Here we present evidence for the location of a second prostate cancer susceptibility gene, which by heterogeneity estimates accounts for approximately 16% of HPC cases. This HPC locus resides on the X chromosome (Xq27-28), a finding consistent with results of previous population-based studies suggesting an X-linked mode of HPC inheritance. Linkage to Xq27-28 was observed in a combined study population of 360 prostate cancer families collected at four independent sites in North America, Finland and Sweden. A maximum two-point lod score of 4.60 was observed at DXS1113, theta=0.26, in the combined data set. Parametric multipoint and non-parametric analyses provided results consistent with the two-point analysis. Significant evidence for genetic locus heterogeneity was observed, with similar estimates of the proportion of linked families in each separate family collection. Genetic mapping of the locus represents an important initial step in the identification of an X-linked gene implicated in the aetiology of HPC.

Major susceptibility locus for prostate cancer on chromosome 1 suggested by a genome-wide search.

Despite its high prevalence, very little is known regarding genetic predisposition to prostate cancer. A genome-wide scan performed in 66 high-risk prostate cancer families has provided evidence of linkage to the long arm of chromosome 1 (1q24-25). Analysis of an additional set of 25 North American and Swedish families with markers in this region resulted in significant evidence of linkage in the combined set of 91 families. The data provide strong evidence of a major prostate cancer susceptibility locus on chromosome 1.