Analysis of PALB2 gene in BRCA1/BRCA2 negative Spanish hereditary breast/ovarian cancer families with pancreatic cancer cases.

BACKGROUND: The PALB2 gene, also known as FANCN, forms a bond and co-localizes with BRCA2 in DNA repair. Germline mutations in PALB2 have been identified in approximately 1% of familial breast cancer and 3-4% of familial pancreatic cancer. The goal of this study was to determine the prevalence of PALB2 mutations in a population of BRCA1/BRCA2 negative breast cancer patients selected from either a personal or family history of pancreatic cancer. METHODS: 132 non-BRCA1/BRCA2 breast/ovarian cancer families with at least one pancreatic cancer case were included in the study. PALB2 mutational analysis was performed by direct sequencing of all coding exons and intron/exon boundaries, as well as multiplex ligation-dependent probe amplification. RESULTS: Two PALB2 truncating mutations, the c.1653T>A (p.Tyr551Stop) previously reported, and c.3362del (p.Gly1121ValfsX3) which is a novel frameshift mutation, were identified. Moreover, several PALB2 variants were detected; some of them were predicted as pathological by bioinformatic analysis. Considering truncating mutations, the prevalence rate of our population of BRCA1/2-negative breast cancer patients with pancreatic cancer is 1.5%. CONCLUSIONS: The prevalence rate of PALB2 mutations in non-BRCA1/BRCA2 breast/ovarian cancer families, selected from either a personal or family pancreatic cancer history, is similar to that previously described for unselected breast/ovarian cancer families. Future research directed towards identifying other gene(s) involved in the development of breast/pancreatic cancer families is required.

Detection of a large rearrangement in PALB2 in Spanish breast cancer families with male breast cancer.

It has been demonstrated that monoallelic PALB2 (Partner and Localizer of BRCA2) gene mutations predispose to familial breast cancer. Some of the families reported with germline PALB2 mutations presented male breast cancer as a characteristic clinical feature. Therefore, we wanted to investigate the contribution of germline PALB2 mutations in a set of 131 Spanish BRCA1/BRCA2-negative breast/ovarian cancer families with at least one male breast cancer case. The analysis included direct sequencing of all coding exons and intron/exon boundaries as well as a Multiplex Ligation-dependent Probe Amplification-based analysis of genomic rearrangements. For the first time we have identified a genomic rearrangement of PALB2 gene involving a large deletion from exon 7 to 11 in a breast cancer family. We have also identified several PALB2 variants, but no other obvious deleterious PALB2 mutation has been found. Thus, our study does not support an enrichment of PALB2 germline mutations in the subset of breast cancer families with male breast cancer cases. The identification of intronic and exonic variants indicates the necessity of assessing the implications of variants that do not lead to PALB2 truncation in the pathoghenicity of the PALB2 gene.

Evidence for a link between TNFRSF11A and risk of breast cancer.

Intracellular signaling mediated by the receptor activator of nuclear factor-κB [Rank, encoded by the tumor necrosis factor receptor superfamily, member 11a (Tnfrsf11a) gene] is fundamental for mammary gland development in mice, regulating the expansion of stem and progenitor cell compartments. Conversely, Rank overexpression in mice promotes abnormal proliferation and impairs differentiation, leading to an increased incidence of tumorigenesis. Here, we show that a common genetic variant near the 5'-end of TNFRSF11A, rs7226991, is associated with breast cancer risk in the general population and among carriers of mutations in the breast cancer 2, early onset (BRCA2) gene. Akin to the results of the Cancer and Genetics Markers of Susceptibility initiative, combined analysis of rs7226991 in two Spanish case-control studies (1,365 controls and 1,323 cases in total) revealed a significant association with risk: odds ratio (OR) = 0.88, 95% confidence interval (CI) 0.78-0.98, P (trend) = 0.025. Subsequent examination of BRCA1 (n = 1,017) and BRCA2 (n = 885) mutation carriers revealed a consistent association in the latter group: weighted hazard ratio ((w)HR) = 0.70; 95% CI 0.55-0.88; and P (trend) = 0.003; compared to BRCA1 mutation carriers, (w)HR = 0.91; 95% CI 0.76-1.10; and P (trend) = 0.33. The results of this study need to be replicated in other populations and with larger numbers of BRCA1/2 mutation carriers.

International distribution and age estimation of the Portuguese BRCA2 c.156_157insAlu founder mutation.

The c.156_157insAlu BRCA2 mutation has so far only been reported in hereditary breast/ovarian cancer (HBOC) families of Portuguese origin. Since this mutation is not detectable using the commonly used screening methodologies and must be specifically sought, we screened for this rearrangement in a total of 5,443 suspected HBOC families from several countries. Whereas the c.156_157insAlu BRCA2 mutation was detected in 11 of 149 suspected HBOC families from Portugal, representing 37.9% of all deleterious mutations, in other countries it was detected only in one proband living in France and in four individuals requesting predictive testing living in France and in the USA, all being Portuguese immigrants. After performing an extensive haplotype study in carrier families, we estimate that this founder mutation occurred 558 ± 215 years ago. We further demonstrate significant quantitative differences regarding the production of the BRCA2 full length RNA and the transcript lacking exon 3 in c.156_157insAlu BRCA2 mutation carriers and in controls. The cumulative incidence of breast cancer in carriers did not differ from that of other BRCA2 and BRCA1 pathogenic mutations. We recommend that all suspected HBOC families from Portugal or with Portuguese ancestry are specifically tested for this rearrangement.

Parity and the risk of breast and ovarian cancer in BRCA1 and BRCA2 mutation carriers.

Environmental or lifestyle factors are likely to explain part of the heterogeneity in breast and ovarian cancer risk among BRCA1 and BRCA2 mutation carriers. We assessed parity as a risk modifier in 515 and 503 Spanish female carriers of mutations in BRCA1 and BRCA2, respectively. Hazard ratios (HR) and their corresponding 95% confidence intervals (CI) were estimated using weighted Cox proportional hazards regression, adjusted for year of birth and study centre. The results for ever being parous and number of live-births were very similar for carriers of mutations in both genes. For all mutation carriers combined, the estimated HR associated with ever having had a live-birth was 0.74 (95% confidence interval [CI] = 0.55-1.01, P = 0.06), and that associated with each live-birth was 0.87 (95%CI = 0.77-0.98, P = 0.02). The latter association was observed only in women aged 40 and above (HR = 0.81, 95%CI = 0.70-0.94, P = 0.004 vs. HR = 0.99, 95%CI = 0.83-1.18, P = 0.9 for women under age 40), and this trend was highly consistently observed for carriers of mutations in each gene. There was no evidence of an association between breast cancer risk and age at first birth for parous BRCA1 or BRCA2 mutation carriers (P-trend >or= 0.3). The power to detect associations with ovarian cancer risk was much lower, especially for BRCA2 mutation carriers. Nevertheless, having a live-birth was associated with protection for BRCA1 mutation carriers (HR = 0.41, 95%CI = 0.18-0.94, P = 0.03), and a strong and consistent protective effect of age at first birth was observed for parous carriers of mutations in both genes (HR = 0.65, 95%CI = 0.52-0.83, P < 0.001). This is the third independent study to find that, as in the general population, parity appears to be associated with protection from breast cancer in women with mutations in BRCA1 and BRCA2. Parity appears to be protective for ovarian cancer in BRCA1 mutation carriers, but its role in BRCA2 mutation carriers remains unclear. Whether later age at first birth is also protective for ovarian cancer in mutation carriers requires further confirmation.

Study of apoptosis and related proteins, CRH and hpGH in placentas of newborns small for gestational age (SGA).

UNLABELLED: The aim of this study is to quantify the expression of apoptotic genes and genes related to the development and growth in placentas of pregnancies with IUGR (intrauterine growth restriction) and normal placentas. We studied the expression of Bcl-2, Caspase3, hpGH (human placental growth hormone) and CRH (corticotropin releasing hormone) genes in normal and IUGR placentas. In addition we have demonstrated this expression by immunohistochemical techniques. MATERIAL AND METHODS: Placentas of newborns with intrauterine infections, complicated pregnancies, congenital malformations and birth asphyxia were excluded. RNA extraction and purification. Total RNA was extracted and cleansed from the lysate using RNA wiz (Ambion) and Qiagen Rneasy Mini (Qiagen). cDNA synthesis. This assay was performed using the Retroscript Kit, Ambion. RT-PCR was performed with the LightCycler System 2.0 (Roche Diagnostics) and the LightCycler FastStart DNA Master Plus SYBR Green I. An immunochemical study was performed using the Envision Plus Dako protocol. RESULTS: Bcl-2, hpGH and CRH are down regulated in the SGA group in comparison to the control group. Caspase3 is up regulated in the SGA group in comparison to the control group. We demonstrated that in placentas from pregnancies with IUGR, expression of Bcl-2is diminished and expression of caspase 3 is augmented compared to normal placentas.

The average cumulative risks of breast and ovarian cancer for carriers of mutations in BRCA1 and BRCA2 attending genetic counseling units in Spain.

PURPOSE: It is not clear that the published estimates of the breast and ovarian cancer penetrances of mutations in BRCA1 and BRCA2 can be used in genetic counseling in countries such as Spain, where the incidence of breast cancer in the general population is considerably lower, the prevalence of BRCA2 mutations seems to be higher, and a distinct spectrum of recurrent mutations exists for both genes. We aimed to estimate these penetrances for women attending genetic counseling units in Spain. EXPERIMENTAL DESIGN: We collected phenotype and genotype data on 155 BRCA1 and 164 BRCA2 mutation carrier families from 12 centers across the country. Average age-specific cumulative risks of breast cancer and ovarian cancer were estimated using a modified segregation analysis method. RESULTS: The estimated average cumulative risk of breast cancer to age 70 years was estimated to be 52% [95% confidence interval (95% CI), 26-69%] for BRCA1 mutation carriers and 47% (95% CI, 29-60%) for BRCA2 mutation carriers. The corresponding estimates for ovarian cancer were 22% (95% CI, 0-40%) and 18% (95% CI, 0-35%), respectively. There was some evidence (two-sided P = 0.09) that 330A>G (R71G) in BRCA1 may have lower breast cancer penetrance. CONCLUSIONS: These results are consistent with those from a recent meta-analysis of practically all previous penetrance studies, suggesting that women with BRCA1 and BRCA2 mutations attending genetic counseling services in Spain have similar risks of breast and ovarian cancer to those published for other Caucasian populations. Carriers should be fully informed of their mutation- and age-specific risks to make appropriate decisions regarding prophylactic interventions such as oophorectomy.