Emma D'Andrea

Association between BRCA1 and BRCA2 mutations and survival in women with invasive epithelial ovarian cancer

CONTEXT Approximately 10% of women with invasive epithelial ovarian cancer (EOC) carry deleterious germline mutations in BRCA1 or BRCA2. A recent article suggested that BRCA2-related EOC was associated with an improved prognosis, but the effect of BRCA1 remains unclear. OBJECTIVE To characterize the survival of BRCA carriers with EOC compared with noncarriers and to determine whether BRCA1 and BRCA2 carriers show similar survival patterns. DESIGN, SETTING, AND PARTICIPANTS A pooled analysis of 26 observational studies on the survival of women with ovarian cancer, which included data from 1213 EOC cases with pathogenic germline mutations in BRCA1 (n = 909) or BRCA2 (n = 304) and from 2666 noncarriers recruited and followed up at variable times between 1987 and 2010 (the median year of diagnosis was 1998). MAIN OUTCOME MEASURE Five-year overall mortality. RESULTS The 5-year overall survival was 36% (95% CI, 34%-38%) for noncarriers, 44% (95% CI, 40%-48%) for BRCA1 carriers, and 52% (95% CI, 46%-58%) for BRCA2 carriers. After adjusting for study and year of diagnosis, BRCA1 and BRCA2 mutation carriers showed a more favorable survival than noncarriers (for BRCA1: hazard ratio [HR], 0.78; 95% CI, 0.68-0.89; P < .001; and for BRCA2: HR, 0.61; 95% CI, 0.50-0.76; P < .001). These survival differences remained after additional adjustment for stage, grade, histology, and age at diagnosis (for BRCA1: HR, 0.73; 95% CI, 0.64-0.84; P < .001; and for BRCA2: HR, 0.49; 95% CI, 0.39-0.61; P < .001). The BRCA1 HR estimate was significantly different from the HR estimated in the adjusted model (P for heterogeneity = .003). CONCLUSION Among patients with invasive EOC, having a germline mutation in BRCA1 or BRCA2 was associated with improved 5-year overall survival. BRCA2 carriers had the best prognosis.

Penetrances of breast and ovarian cancer in a large series of families tested for BRCA1/2 mutations.

Accurate estimates of breast and ovarian cancer penetrance in BRCA1/2 mutation carriers are crucial in genetic counseling. Estimation is difficult because of the low frequency of mutated alleles and the often-uncertain mechanisms of family ascertainment. We estimated the penetrances of breast and ovarian cancers in carriers of BRCA1/2 mutations by maximizing the retrospective likelihood of the genetic model, given the observed test results, in 568 Italian families screened for germline mutations. The software BRCAPRO was used as a probability calculation tool in a Markov Chain Monte Carlo approach. Breast cancer penetrances were 27% (95% CI 20–34%) at age 50 years and 39% (27–52%) at age 70 in BRCA1 carriers, and 26% (0.18–0.34%) at age 50 and 44% (29–58%) at age 70 in BRCA2 carriers, and ovarian cancer penetrances were 14% (7–22%) at age 50 and 43% (21–66%) at age 70 in BRCA1 carriers and 3% (0–7%) at age 50 and 15% (4–26%) at age 70 in BRCA2 carriers. The new model gave a better fit than the current default in BRCAPRO, the likelihood being 70 log units greater; in addition, the observed numbers of mutations in families stratified by gene and by cancer profile were not significantly different from those expected. Our new penetrance functions are appropriate for predicting breast cancer risk, and for determining the probability of carrying BRCA1/2 mutations, in people who are presently referred to genetic counseling in Italy. Our approach could lead to country-customized versions of the BRCAPRO software by providing appropriate population-specific estimates.

Lack of association between androgen receptor CAG polymorphism and familial breast/ovarian cancer.

The human androgen receptor (AR) gene contains a highly polymorphic CAG repeat in exon 1 that is inversely correlated with AR transcriptional activity in vitro. Several studies have shown that fewer CAG repeats are associated with an increased risk as well as more aggressive forms of prostate cancer. More recently, AR allele length was also inversely correlated with the histological grade of breast cancer, but no association was found between the AR-CAG polymorphism and the risk of either breast or ovary cancer. On the contrary, it was proposed that a longer CAG repeat sequence might be associated with an increased risk of breast cancer in BRCA1 mutation carriers, thus suggesting a different role of the AR-CAG polymorphism in sporadic and inherited breast cancers. With the intent of better understanding the role of the AR-CAG polymorphism as a cancer risk modifier, we defined the AR genotype of 151 patients (101 with breast and 50 with ovary cancer) belonging to high-risk breast/ovary cancer families. No difference in CAG repeat length was found between either breast and ovary cancer patients or age at diagnosis of both tumors. These results were also confirmed in a sub-group of 47 breast cancer cases, that either carried a BRCA gene mutation (11 cases) or were identified by very stringent operational criteria as hereditary breast cancers. Even though a substantially larger sample size would be required to reach conclusive evidence, our findings suggest that the AR-CAG polymorphism does not act as a modifier of tumor onset or tumor phenotype in breast/ovarian cancer families.

Evaluation of widely used models for predicting BRCA1 and BRCA2 mutations

Deleterious mutations of the BRCA1 and BRCA2 genes are a major risk factor for the development of breast and ovarian cancers.1–4 Mutation tests for these two genes commonly are now offered in specialised clinics.5,6 As a result, a large number of women with personal or family histories of breast or ovarian cancer seek genetic counselling. Accurate evaluation of the probability that a woman carries a germline pathogenic mutation at BRCA1 or BRCA2 therefore is essential to help counsellors and those being counselled to decide whether testing is appropriate. In this context, the questions of practical interest are: Given the pedigree, what is the chance of a mutation being present? and What is the chance of the DNA laboratory finding a mutation? After testing became available, several models were developed to assess the pre-test probability of identifying carriers of mutations. Broadly speaking, two different approaches have been used to develop predictive models: the “empirical approach” and the “Mendelian approach”.7 In empirical models, families are stratified according to variables that describe their family history; regression or other approaches are used to predict the results of Mendelian testing. In some cases, this approach simply consists of observing the proportion of mutations found in different strata. Mendelian models, in contrast, address the probability that a proband is a mutation carrier on the basis of explicit assumptions about the genetic parameters (allele frequencies and cancer penetrances in carriers and non-carriers) and the Mendelian rules of gene transmission. A consequence of the two different strategies is that the Mendelian models evaluate the probability that a proband is a gene carrier, whereas the empirical models evaluate the probability of identifying a mutation. The main purpose of this study was to compare the performances of published models in predicting mutation test results in …

Prevalence of BRCA1 genomic rearrangements in a large cohort of Italian breast and breast/ovarian cancer families without detectable BRCA1 and BRCA2 point mutations

The presence of genomic rearrangements of the BRCA1 gene in breast and/or ovarian cancer families has been intensively investigated in patients from various countries over the last years. A number of different rearrangements have been reported by several studies that clearly document the involvement of this mutation type in genetic predisposition to breast and ovarian cancer. Population‐specific studies are now needed to evaluate the prevalence of genomic rearrangements before deciding whether to include ad hoc screening procedures into standard diagnostic mutation detection approaches. Indeed, the vast majority of the studies have been performed on small, highly selected, sample sets because of the limitations imposed by the laborious technical approaches. Moreover, prevalence figures are likely to differ across different countries according to the ethnic origin of each specific population. Here we analyze a large cohort of 653 Italian probands, negative for BRCA1 and BRCA2 point mutations, gathered from four National Institutions. We report the identification of BRCA1 genomic rearrangements in 12 independent families. Noteworthy, half of the probands carry mutations that recur in more than one Italian family. Considering the whole spectrum of Italian BRCA1 gene rearrangements identified thus far in consecutive patients, we estimate that alterations of this type account for 19% (95% CI: 0.11 < 0.19 < 0.28) of the BRCA1 mutation positive families. We conclude that the search for major genomic rearrangements is essential for an accurate and comprehensive BRCA1 mutation detection strategy in Italy.

Epstein-Barr virus-associated post-transplant lympho-proliferative disease of donor origin in liver transplant recipients

BACKGROUND/AIMS Post-transplant lymphoproliferative disease, a potential complication of solid organ transplantation, occurs in about 3% of orthotopic liver transplant recipients. We report the genetic and virological characterization of two cases of post-transplant lymphoproliferative disease that occurred early (4 and 6 months) after orthotopic liver transplant as large-cell non-Hodgkins lymphomas located at the hepatic hilum. METHODS Lymphomatous tissues were analyzed for clonality and presence of Epstein-Barr virus (EBV) sequences by Southern blot, polymerase chain reaction, and in situ hybridization techniques. RESULTS The tumors in both cases were sustained by a clonal proliferation of B lymphocytes containing type A EBV DNA. Moreover, in situ hybridization with a digoxigenin-labeled EBV-specific probe evidenced a strong nuclear signal in most of the neoplastic cells. DNA microsatellite analysis at three different loci detected alleles of donor origin in both tumor samples, suggesting that the neoplastic B cells were of donor origin. CONCLUSIONS EBV-infected donor B lymphocytes might be responsible for intragraft post-transplant lymphoproliferative disease in orthotopic liver transplant recipients. As 20 to 30% of post-transplant lymphomas involve the graft itself, donor-derived post-transplant lymphoproliferative disease might be more frequent than presently appreciated. Prospective studies are needed to assess its real incidence and identify possible risk factors.

Hashimoto's Thyroiditis and Graves' Disease Associated with Retroperitoneal Fibrosis

Retroperitoneal fibrosis is a rare disease of uncertain pathogenesis. However, its possible association with several immunopathologic conditions, the possibility of systemic involvement by the fibrous process, the presence of various autoantibodies, and the frequent response to immunosuppressive treatment all support an autoimmune pathogenesis. Riedels thyroiditis is a rare disease the pathogenesis of which is also thought to be immune-mediated based on its optimal response to steroids; Riedels thyroiditis is also frequently reported in association with retroperitoneal fibrosis. We describe here two cases of autoimmune thyroid disease associated with retroperitoneal fibrosis, the first with features of primary myxedema, the second of primary thyrotoxicosis. Histology of retroperitoneal fibrosis is documented and it is compatible with an immunopathologic condition. Thus, these two cases add further support to the hypothesis of an autoimmune pathogenesis of retroperitoneal fibrosis and indicate the importance of carefully monitoring for the development of other autoimmune disorders, i.e., of the thyroid gland, in patients with retroperitoneal fibrosis.

Anomalous Transcripts and Allelic Deletions of the FHIT Gene in Human Esophageal Cancer

The fragile histidine triad (FHIT) gene is localized on chromosome 3p14 and spans the common fragile site FRA3B. Even though its role in carcinogenesis is still unclear, this gene is frequently inactivated by carcinogen-induced intragenic deletions in many types of cancers, and FHIT abnormal transcripts are found in many primary tumors and tumor-derived cell lines. We evaluated FHIT gene involvement in 39 esophageal carcinomas (18 adenocarcinomas [AC¿, 21 squamous cell carcinomas [SCC]) by both reverse transcriptase-polymerase chain reaction (RT-PCR) amplification and loss of heterozygosity analysis (LOH). Thirty cases (77%) displayed either aberrant FHIT transcripts (12 cases) and/or LOH (24 cases); among these, only 6 samples displayed both aberrant transcripts and LOH, thus suggesting that the two events are probably independent. Moreover, LOH was significantly higher in SCC (80%) than in AC (44%), and because most of our patients are heavy smokers and/or alcohol consumers, these results suggest that the FHIT gene might be a common target for carcinogens also in the esophagus.

Uncoupling of Growth-Inhibition and Differentiation in Dexamethasone-Treated Human Rhabdomyosarcoma Cells

The effects of dexamethasone, a synthetic glucocorticoid, and of N,N-dimethylformamide on in vitro growth and differentiation and on proto-oncogene expression of human rhabdomyosarcoma cells were studied. RD/18 clone cells (derived from the embryonal rhabdomyosarcoma cell line RD) treated with 100 nM dexamethasone showed an almost complete block of differentiation: about 5% myosin-positive cells were observed after 2 weeks of culture in dexamethasone-supplemented differentiation medium, compared to 20% of untreated cultures. Dexamethasone also induced a 20-30% growth inhibition and a more flattened morphology. The treatment with N,N-dimethylformamide induced a significantly increased proportion of myosin-positive cells (reaching about 30%) and a 40% growth inhibition. Induction of differentiation inversely correlated with the levels of c-myc proto-oncogene expression: after a 2 week culture dexamethasone-treated cells showed the highest c-myc expression and N,N-dimethylformamide-treated cells the lowest. Culture conditions per se down-modulated c-erbB1 and up-regulated c-jun expression, with no relationship to the differentiation pattern. Other proto-oncogenes were not expressed (c-sis, N-myc, c-mos, c-myb) or were not modulated (c-fos, c-raf). Therefore dexamethasone and N,N-dimethylformamide, both causing a decreased growth rate, showed opposing actions on myogenic differentiation and on c-myc proto-oncogene expression of human rhabdomyosarcoma cells.

CDKN2A Unclassified Variants in Familial Malignant Melanoma: Combining Functional and Computational Approaches for Their Assessment

CDKN2A codes for two oncosuppressors by alternative splicing of two first exons: p16INK4a and p14ARF. Germline mutations are found in about 40% of melanoma‐prone families, and most of them are missense mutations mainly affecting p16INK4a. A growing number of p16INK4a variants of uncertain significance (VUS) are being identified but, unless their pathogenic role can be demonstrated, they cannot be used for identification of carriers at risk. Predicting the effect of these VUS by either a “standard” in silico approach, or functional tests alone, is rather difficult. Here, we report a protocol for the assessment of any p16INK4a VUS, which combines experimental and computational tools in an integrated approach. We analyzed p16INK4a VUS from melanoma patients as well as variants derived through permutation of conserved p16INK4a amino acids. Variants were expressed in a p16INK4a‐null cell line (U2‐OS) and tested for their ability to block proliferation. In parallel, these VUS underwent in silico prediction analysis and molecular dynamics simulations. Evaluation of in silico and functional data disclosed a high agreement for 15/16 missense mutations, suggesting that this approach could represent a pilot study for the definition of a protocol applicable to VUS in general, involved in other diseases, as well.