Germline brca2 sequence variants in patients with ocular melanoma

On the basis, chiefly, of anecdotal reports of cases of ocular melanoma (OM) occurring in families with inherited susceptibility to breast cancer due to brca2 germline mutations, we examined the frequency of brca2 alterations in a series of 62 ocular melanoma cases. These cases were preferentially selected on the basis of reported family history of breast or ovarian cancer, or OM, although the series also included a randomly selected set of cases without family history of cancer. A total of 7 germline alterations were found, of which 3 were likely to be associated with disease. While all 3 deleterious mutations were found in patients who also had a personal history of breast cancer, only 1 of the 3 families had a family history of breast/ovarian cancer or OM. Although germline brca2 mutations may account for a small proportion of all OM cases, there may be additional loci that contribute to familial aggregation of OM and to the familial association between OM and breast cancer.

The role of genetic factors in predisposition to squamous cell cancer of the head and neck

© 1999 Cancer Research Campaign

Multifactorial analysis of differences between sporadic breast cancers and cancers involving BRCA1 and BRCA2 mutations

BACKGROUND

We have previously demonstrated that breast cancers associated with inherited BRCA1 and BRCA2 gene mutations differ from each other in their histopathologic appearances and that each of these types differs from breast cancers in patients unselected for family history (i.e., sporadic cancers). We have now conducted a more detailed examination of cytologic and architectural features of these tumors.

METHODS

Specimens of tumor tissue (5-microm-thick sections) were examined independently by two pathologists, who were unaware of the case or control subject status, for the presence of cell mitosis, lymphocytic infiltration, continuous pushing margins, and solid sheets of cancer cells; cell nuclei, cell nucleoli, cell necrosis, and cell borders were also evaluated. The resulting data were combined with previously available information on tumor type and tumor grade and further evaluated by multifactorial analysis. All statistical tests are two-sided.

RESULTS

Cancers associated with BRCA1 mutations exhibited higher mitotic counts (P = .001), a greater proportion of the tumor with a continuous pushing margin (P<.0001), and more lymphocytic infiltration (P = .002) than sporadic (i.e., control) cancers. Cancers associated with BRCA2 mutations exhibited a higher score for tubule formation (fewer tubules) (P = .0002), a higher proportion of the tumor perimeter with a continuous pushing margin (P<.0001), and a lower mitotic count (P = .003) than control cancers.

CONCLUSIONS

Our study has identified key features of the histologic phenotypes of breast cancers in carriers of mutant BRCA1 and BRCA2 genes. This information may improve the classification of breast cancers in individuals with a family history of the disease and may ultimately aid in the clinical management of patients.

Germ-line mutation analysis in patients with multiple endocrine neoplasia type 1 and related disorders

Multiple endocrine neoplasia type 1 (MEN1) is an autosomal dominant syndrome predisposing to tumors of the parathyroid, endocrine pancreas, anterior pituitary, adrenal glands, and diffuse neuroendocrine tissues. The MEN1 gene has been assigned, by linkage analysis and loss of heterozygosity, to chromosome 11q13 and recently has been identified by positional cloning. In this study, a total of 84 families and/or isolated patients with either MEN1 or MEN1-related inherited endocrine tumors were screened for MEN1 germ-line mutations, by heteroduplex and sequence analysis of the MEN1 gene-coding region and untranslated exon 1. Germ-line MEN1 alterations were identified in 47/54 (87%) MEN1 families, in 9/11 (82%) isolated MEN1 patients, and in only 6/19 (31.5%) atypical MEN1-related inherited cases. We characterized 52 distinct mutations in a total of 62 MEN1 germ-line alterations. Thirty-five of the 52 mutations were frameshifts and nonsense mutations predicted to encode for a truncated MEN1 protein. We identified eight missense mutations and five in-frame deletions over the entire coding sequence. Six mutations were observed more than once in familial MEN1. Haplotype analysis in families with identical mutations indicate that these occurrences reflected mainly independent mutational events. No MEN1 germ-line mutations were found in 7/54 (13%) MEN1 families, in 2/11 (18%) isolated MEN1 cases, in 13/19 (68. 5%) MEN1-related cases, and in a kindred with familial isolated hyperparathyroidism. Two hundred twenty gene carriers (167 affected and 53 unaffected) were identified. No evidence of genotype-phenotype correlation was found. Age-related penetrance was estimated to be >95% at age >30 years. Our results add to the diversity of MEN1 germ-line mutations and provide new tools in genetic screening of MEN1 and clinically related cases.

Haplotype and phenotype analysis of nine recurrent BRCA2 mutations in 111 families: results of an international study

Several BRCA2 mutations are found to occur in geographically diverse breast and ovarian cancer families. To investigate both mutation origin and mutation-specific phenotypes due to BRCA2, we constructed a haplotype of 10 polymorphic short tandem-repeat (STR) markers flanking the BRCA2 locus, in a set of 111 breast or breast/ovarian cancer families selected for having one of nine recurrent BRCA2 mutations. Six of the individual mutations are estimated to have arisen 400-2,000 years ago. In particular, the 6174delT mutation, found in approximately 1% of individuals of Ashkenazi Jewish ancestry, was estimated to have arisen 29 generations ago (1-LOD support interval 22-38). This is substantially more recent than the estimated age of the BRCA1 185delAG mutation (46 generations), derived from our analogous study of BRCA1 mutations. In general, there was no evidence of multiple origins of identical BRCA2 mutations. Our study data were consistent with the previous report of a higher incidence of ovarian cancer in families with mutations in a 3.3-kb region of exon 11 (the ovarian cancer cluster region [OCCR]) (P=.10); but that higher incidence was not statistically significant. There was significant evidence that age at diagnosis of breast cancer varied by mutation (P<.001), although only 8% of the variance in age at diagnosis could be explained by the specific mutation, and there was no evidence of family-specific effects. When the age at diagnosis of the breast cancer cases was examined by OCCR, cases associated with mutations in the OCCR had a significantly older mean age at diagnosis than was seen in those outside this region (48 years vs. 42 years; P=.0005).

Genetic heterogeneity and penetrance analysis of the BRCA1 and BRCA2 genes in breast cancer families. The Breast Cancer Linkage Consortium

The contribution of BRCA1 and BRCA2 to inherited breast cancer was assessed by linkage and mutation analysis in 237 families, each with at least four cases of breast cancer, collected by the Breast Cancer Linkage Consortium. Families were included without regard to the occurrence of ovarian or other cancers. Overall, disease was linked to BRCA1 in an estimated 52% of families, to BRCA2 in 32% of families, and to neither gene in 16% (95% confidence interval [CI] 6%-28%), suggesting other predisposition genes. The majority (81%) of the breast-ovarian cancer families were due to BRCA1, with most others (14%) due to BRCA2. Conversely, the majority of families with male and female breast cancer were due to BRCA2 (76%). The largest proportion (67%) of families due to other genes was found in families with four or five cases of female breast cancer only. These estimates were not substantially affected either by changing the assumed penetrance model for BRCA1 or by including or excluding BRCA1 mutation data. Among those families with disease due to BRCA1 that were tested by one of the standard screening methods, mutations were detected in the coding sequence or splice sites in an estimated 63% (95% CI 51%-77%). The estimated sensitivity was identical for direct sequencing and other techniques. The penetrance of BRCA2 was estimated by maximizing the LOD score in BRCA2-mutation families, over all possible penetrance functions. The estimated cumulative risk of breast cancer reached 28% (95% CI 9%-44%) by age 50 years and 84% (95% CI 43%-95%) by age 70 years. The corresponding ovarian cancer risks were 0.4% (95% CI 0%-1%) by age 50 years and 27% (95% CI 0%-47%) by age 70 years. The lifetime risk of breast cancer appears similar to the risk in BRCA1 carriers, but there was some suggestion of a lower risk in BRCA2 carriers <50 years of age.

Risk and penetrance of primary hyperparathyroidism in multiple endocrine neoplasia type 2A families with mutations at codon 634 of the RET proto-oncogene. Groupe D'etude des Tumeurs à Calcitonine

Germline mutations of the RET proto-oncogene are responsible for multiple endocrine neoplasia type 2, including multiple endocrine type 2A (MEN 2A), type 2B (MEN 2B), and familial medullary thyroid carcinoma. The relationship between specific mutations and syndromic features has been established. In particular, the risk for pheochromocytoma and hyperparathyroidism (HPT) in MEN 2A patients is clearly associated with the presence of the RET mutation at a specific position, i.e. at codon 634. Also, a correlation between a specific mutation, C634R, and the development of HPT has been suggested but is still controversial. To further investigate the relationship between specific mutations of codon 634 and the development of HPT, we studied a population of 188 individuals, carrying mutations at codon 634, namely C634R (65 patients belonging to 10 families), C634Y (80 patients belonging to 11 families), or the less frequent codon 634 mutations [i.e. C634S, C634F, C634G, or C634W (43 patients belonging to 9 families)]. In this series of patients, we defined an overall HPT prevalence of 19.1% and found that this prevalence did not vary significantly, with respect to the nature of the mutation. However, irrespective of the particular mutation, the prevalence of HPT showed a high interfamilial variability. The statistical model that best fitted with the observed data was in favor of the heterogeneity of the risk for HPT, with 40% of the families showing an HPT risk of 34% and 60% of the families showing an HPT risk of 9%. In addition, our study clearly demonstrated that HPT could be an early component of the disease and provided the first estimate of age-specific and mutation-specific HPT penetrance in individuals with mutations of codon 634 of the RET proto-oncogene.

Mutations in BRCA1 and BRCA2 in breast cancer families: are there more breast cancer-susceptibility genes?

To estimate the proportion of breast cancer families due to BRCA1 or BRCA2, we performed mutation screening of the entire coding regions of both genes supplemented with linkage analysis of 31 families, 8 containing male breast cancers and 23 site-specific female breast cancer. A combination of protein-truncation test and SSCP or heteroduplex analyses was used for mutation screening complemented, where possible, by the analysis of expression level of BRCA1 and BRCA2 alleles. Six of the eight families with male breast cancer revealed frameshift mutations, two in BRCA1 and four in BRCA2. Although most families with female site-specific breast cancers were thought to be due to mutations in either BRCA1 or BRCA2, we identified only eight mutations in our series of 23 site-specific female breast cancer families (34%), four in BRCA1 and four in BRCA2. According to the posterior probabilities calculated for mutation-negative families, based on linkage data and mutation screening results, we would expect 8-10 site-specific female breast cancer families of our series to be due to neither BRCA1 nor BRCA2. Thus, our results suggest the existence of at least one more major breast cancer-susceptibility gene.

The carrier frequency of the BRCA2 6174delT mutation among Ashkenazi Jewish individuals is approximately 1%

Certain germline mutations in either BRCA1 or BRCA2 confer a lifetime risk of developing breast cancer that may approach 90%. The BRCA1 185delAG mutation was found in 20% and the BRCA2 6174delT mutation in 8% of Ashkenazi Jewish women with early-onset breast cancer. The 185delAG mutation was observed in 0.9% of 858 Ashkenazi Jews unselected for a personal or family history of cancer. Assuming comparable age-specific penetrances, a carrier frequency of 0.3% was estimated for the 6174delT BRCA2 mutation. To test this hypothesis, we performed a population survey of 1,255 Jewish individuals. In two independent groups, a prevalence of approximately 1% (C.I. 0.6-1.5) was observed for the 6174delT mutation. The relative risk of developing breast cancer by age 42 was estimated to be 9.3 (C.I. 2.5-22.5) for 6174delT, compared to 31 (C.I. 11-77) for 185delAG. Analysis of 107 Ashkenazi Jewish women with breast cancer and a family history of breast or ovarian cancer confirmed a four-fold greater prevalence for the BRCA1 185delAG mutation compared to the BRCA2 6174delT mutation. Our findings suggest a difference in cumulative life-time penetrance for the two mutations. Genetic counseling for the one in 50 Ashkenazi Jewish individuals harbouring specific germline mutations in BRCA1 or BRCA2 must be tailored to reflect the different risks associated with the two mutations.

Germline BRCA1 185delAG mutations in Jewish women with breast cancer

BACKGROUND

We aimed to find out the proportion of breast cancers in Ashkenazi Jewish women attributable to the frameshift mutation at position 185 involving the deletion of adenine and guanine (185delAG) in the breast cancer gene BRCA1.

METHODS

We studied 107 Ashkenazi Jewish women with breast cancer seen at medical oncology and genetic counseling clinics in New York over a three and a half year period beginning in 1992. 80 of the women were diagnosed before age 42 years; the other 27 were diagnosed between 42 and 50 years and had a positive family history. Genomic DNA testing by PCR amplification was done to identify any 185delAG mutations of the BRCA1 gene.

FINDINGS

Of the 80 women diagnosed before the age of 42 years, 16 (20%, 95% CI 11.2-28.8) were heterozygous for the mutation. All 16 women had at least one first-degree or second-degree relative with breast or ovarian cancer. Of 27 probands diagnosed with breast cancer between the ages of 42 and 50 years who had at least one first-degree relative affected with breast or ovarian cancer, 8 (30%, 95% CI 12-47) had 185delAG mutations.

INTERPRETATION

These data suggest that screening for the 185delAG mutation may be useful in genetic counselling of these women where options for detection and prevention of possible cancers can be discussed.

Recurrent BRCA2 6174delT mutations in Ashkenazi Jewish women affected by breast cancer

The lifetime risk of breast cancer may approach 80-90% in women who have germline mutations of either of two genes, BRCA1 or BRCA2. A single BRCA1 mutation, 185delAG, has been noted in approximately 20% of Ashkenazi Jewish women with early onset breast cancer and in 0.9% of the Ashkenazi population. We recently detected a 6174delT frameshift mutation in BRCA2 in an hereditary breast cancer kindred of Ashkenazi Jewish ancestry. Here, we investigated the frequency of this mutation in 200 women with early-onset breast cancer. Six of 80 Ashkenazi Jewish women (8%) diagnosed with breast cancer before the age of 42, wer heterozygous for the 6174delT mutation, compared to none of 93 non-Jewish women diagnosed with breast cancer at the same age (P = .005). These cases were ascertained without regard to family history. Two of 27 (7%) additional Jewish families in which the proband was diagnosed with breast cancer at age 42 to 50 and had a family history of breast or ovarian cancer had germline 6174delT mutations. The results of this report suggest that a recurrent mutation of BRCA1 and a recurrent mutation BRCA2 together may account for over a quarter of all early-onset breast cancer in the setting of a personal or family history of ovarian cancer in Ashkenazi Jewish women.

Risk modifiers in carriers of BRCA1 mutations

The majority of, but not all, women with mutations in the BRCA1 gene will be affected with breast or ovarian cancer by the age of 70. To establish whether known risk factors modify susceptibility to cancer in these women, we have studied the reproductive histories of 333 North American women who were found by haplotype analysis to carry BRCA1 mutations. An increased risk for breast cancer was associated with low parity and with recent birth cohort. The risk of ovarian cancer decreased with increasing age at last childbirth; however, in contrast to the case for sporadic cancer, the risk of ovarian cancer in BRCA1 carriers was found to increase significantly with increasing parity.

Further localization of the gene for nevoid basal cell carcinoma syndrome (NBCCS) in 15 Australasian families: linkage and loss of heterozygosity

Nevoid basal cell carcinoma syndrome (NBCCS; basal cell nevus syndrome or Gorlin syndrome) is a cancer-predisposition syndrome characterized by multiple basal cell carcinomas (BCCs) and diverse developmental defects. The gene for NBCCS has been mapped to 9q23.1-q31 in North American and European families. In addition, loss of heterozygosity (LOH) for genetic markers in this region has been detected in sporadic BCCs, indicating that the NBCCS gene is probably a tumor-suppressor gene. In this study we have determined that the NBCCS gene is also linked to this region in Australasian pedigrees and that there is no significant evidence of heterogeneity. We have defined the localization of the gene by multipoint and haplotype analysis of 15 families, using four microsatellite markers. LOH at these loci was detected in 50% of sporadic BCCs, a rate that is significantly higher than that in other skin lesions used as controls.

Effect of progestin therapy on cortical and trabecular bone: comparison with estrogen

PURPOSE

To determine the effect of progestin therapy on bone mineral density in postmenopausal women and to compare its effects to those of estrogen.

SUBJECTS AND METHODS

A prospective, randomized clinical trial was performed in 81 postmenopausal women aged 51.7 +/- 4.4 years (mean +/- SD). They were assigned to one of four groups: Provera 20 mg, Premarin 0.6 mg, Premarin 0.3 mg plus Provera 10 mg, and a placebo. In addition, all women received calcium supplementation, if necessary, to a calcium intake of 1,000 mg/day. We used single- and dual-photon absorpiometry, metacarpal radiogrammetry, and computed axial tomography to measure bone mineral density in the total skeleton, spine, radius, and metacarpal.

RESULTS

Women receiving placebo lost bone at all sites (p less than 0.01). The Provera-treated group showed no change in total body calcium, but there were decreases in radial density (p less than 0.01), metacarpal cortex (p less than 0.01), and spine density (p less than 0.01). The Premarin-treated group had an increase in spine density and total body density (p less than 0.05), but a decrease in radial density (p less than 0.05). The Premarin-plus-Provera group showed no change in spine density, total body calcium, or radial density but had a decrease in metacarpal cortex (p less than 0.01).

CONCLUSIONS

Compared to placebo, Provera reduced the rate of loss in cortical areas of the skeleton, but not in the spine, which contains more trabecular bone. In contrast, Premarin reduced the rate of loss in both cortical and trabecular areas of the skeleton. The low-dose combination of Premarin plus Provera was similar in its effect on bone to that of Premarin alone, suggesting that there may be a synergistic effect of this hormone combination on bone. Serum cholesterol levels decreased with Provera, Premarin, and the combination of both, whereas levels of serum triglycerides increased with Premarin treatment, decreased with the Provera regimen, and were unchanged with the combination therapy. Provera does not adversely affect the lipid profile.

Treatment of postmenopausal osteoporosis with high doses of synthetic calcitriol. A randomized controlled study

OBJECTIVE

To study the efficacy of synthetic 1,25 dihydroxyvitamin D3 (calcitriol) in the treatment of osteoporosis.

DESIGN

Two-year, double-blind, randomized clinical trial.

SETTING

University medical center.

PATIENTS

Fifty postmenopausal women with vertebral fractures recruited by referral.

INTERVENTION

Calcium intake was adjusted to 25 mmol/d (1000 mg/d) at baseline. Patients were then randomized to treatment with either calcitriol or placebo. During the study, calcium intake was reduced to 15 mmol/d (600 mg/d) and the dose of calcitriol was adjusted to maintain serum calcium less than 2.74 mmol/L (less than 11.0 mg/dL) or urine calcium less than 9.96 mmol/d (less than 400 mg/d).

MEASUREMENTS AND MAIN RESULTS

After 2 years, the mean dose of calcitriol in the treated group was 0.62 micrograms/d. Bone mineral density of the spine increased 1.94% with calcitriol therapy and decreased 3.92% with placebo (P = 0.001). Total body calcium increased 0.21% with calcitriol therapy and decreased 1.85% with placebo (P = 0.004). Patients receiving placebo had significant decreases in spine density (P = 0.0007) and total body calcium (P = 0.0004). There were no differences in vertebral fracture rates between the groups. Renal function studies were not statistically different between the groups after 2 years.

CONCLUSION

The treatment of postmenopausal osteoporotic women with synthetic calcitriol for 2 years was associated with increases in spine density and total body calcium. No adverse effects on renal function were seen after long-term calcitriol therapy.