Veronica Medici

FANCM c.5791C>T nonsense mutation (rs144567652) induces exon skipping, affects DNA repair activity and is a familial breast cancer risk factor

Numerous genetic factors that influence breast cancer risk are known. However, approximately two-thirds of the overall familial risk remain unexplained. To determine whether some of the missing heritability is due to rare variants conferring high to moderate risk, we tested for an association between the c.5791C>T nonsense mutation (p.Arg1931*; rs144567652) in exon 22 of FANCM gene and breast cancer. An analysis of genotyping data from 8635 familial breast cancer cases and 6625 controls from different countries yielded an association between the c.5791C>T mutation and breast cancer risk [odds ratio (OR) = 3.93 (95% confidence interval (CI) = 1.28-12.11; P = 0.017)]. Moreover, we performed two meta-analyses of studies from countries with carriers in both cases and controls and of all available data. These analyses showed breast cancer associations with OR = 3.67 (95% CI = 1.04-12.87; P = 0.043) and OR = 3.33 (95% CI = 1.09-13.62; P = 0.032), respectively. Based on information theory-based prediction, we established that the mutation caused an out-of-frame deletion of exon 22, due to the creation of a binding site for the pre-mRNA processing protein hnRNP A1. Furthermore, genetic complementation analyses showed that the mutation influenced the DNA repair activity of the FANCM protein. In summary, we provide evidence for the first time showing that the common p.Arg1931* loss-of-function variant in FANCM is a risk factor for familial breast cancer.

A rapid genetic counselling and testing in newly diagnosed breast cancer is associated with high rate of risk-reducing mastectomy in BRCA1/2-positive Italian women

BACKGROUND Risk-reducing mastectomy (RRM) decreases breast cancer (BC) risk in BRCA1/2 mutation carriers by up to 95%, but the Italian attitude towards this procedure is reluctant. PATIENTS AND METHODS This is an observational study with retrospective design, using quantitative and qualitative research methods, aimed at evaluating the attitude towards RRM by rapid genetic counselling and testing (RGCT), at the time of BC diagnosis, compared with traditional genetic counselling and testing (TGCT), after previous BC surgery. Secondary aims were to investigate patient satisfaction after RRM and the rate of occult tumour in healthy breasts. A total of 1168 patients were evaluated: 1058 received TGCT, whereas 110 underwent RGCT. RESULTS In TGCT, among 1058 patients, 209 (19.7%) mutation carriers were identified, with the rate of RRM being 4.7% (10 of 209). Conversely in RGCT, among 110 patients, 36 resulted positive, of which, 15 (41.7%) underwent bilateral mastectomy at the BC surgery time, showing an overall good satisfaction, measured by interpretative phenomenological analysis 12 months after the intervention. CONCLUSIONS Our study shows that RGCT in patients with a hereditary profile is associated with a high rate of RRM at the BC surgery time, this being the pathway offered within a multidisciplinary organization.

Favourable ten-year overall survival in a Caucasian population with high probability of hereditary breast cancer

BackgroundThe purpose of our study was to compare differences in the prognosis of breast cancer (BC) patients at high (H) risk or intermediate slightly (IS) increased risk based on family history and those without a family history of BC, and to evaluate whether ten-year overall survival can be considered a good indicator of BRCA1 gene mutation.MethodsWe classified 5923 breast cancer patients registered between 1988 and 2006 at the Department of Oncology and Haematology in Modena, Italy, into one of three different risk categories according to Modena criteria. One thousand eleven patients at H and IS increased risk were tested for BRCA1/2 mutations. The overall survival (OS) and disease free survival (DFS) were the study end-points.ResultsEighty BRCA1 carriers were identified. A statistically significantly better prognosis was observed for patients belonging to the H risk category with respect to women in the IS and sporadic groups (82% vs.75% vs.73%, respectively; p < 0.0001). Comparing only BRCA1 carriers with BRCA-negative and sporadic BC (77% vs.77% vs.73%, respectively; p < 0.001) an advantage in OS was seen.ConclusionsPatients belonging to a population with a high probability of being BRCA1 carriers had a better prognosis than those with sporadic BC. Considering these results, women who previously had BC and had survived ten years could be selected for BRCA1 analysis among family members at high risk of hereditary BC during genetic counselling. Since only 30% of patients with a high probability of having hereditary BC have BRCA1 mutations, selecting women with a long term survival among this population could increase the rate of positive analyses, avoiding the use of expensive tests.

A novel deletion of BRCA1 gene that eliminates the ATG initiation codon without affecting the promoter region

BACKGROUND Point mutations in the highly penetrant cancer susceptibility gene BRCA1 are responsible for the majority of hereditary breast and/or ovarian cancer. We describe a novel large rearrangement of the BRCA1 gene identified in an Italian woman affected by an early onset bilateral breast cancer and a family history of hereditary breast cancer. The proband and her parents were negative for the presence of point mutations in BRCA1 and BRCA2 genes. METHODS Multiplex ligation-dependent probe amplification (MLPA) was used to detect rearrangements in the BRCA1 gene. The breakpoint of the rearrangement identified in the proband was defined by restriction mapping and PCR amplification. BRCA1 mRNA encoded by the mutant allele was isolated from peripheral blood. RESULTS The proband was heterozygous for a 9.1 kb deletion spanning from intron 1 to intron 3 (g.1238_10350del) that eliminates exons 2 and 3 in the mature mRNA. In mutant mRNA exon 1a joins directly to exon 5 with no disruption of the reading frame. CONCLUSIONS This deletion that eliminates the ATG initiation site in exon 2 and the sequence located in exons 2 and 3 encoding part of the RING finger domain of BRCA1 protein, is expected to abolish the function of this protein.

BRCA1 p.His1673del is a pathogenic mutation associated with a predominant ovarian cancer phenotype

We have investigated the clinical significance of the BRCA1 variant p.His1673del in 14 families from the Emilia-Romagna region of Italy, including 20 breast and 23 ovarian cancer cases; four families displayed site-specific ovarian cancer. The variant, absent in human variation databases, has been reported three times in BRCA1 specific databases; all probands shared the same rare haplotype at the BRCA1 locus, consistent with a common ancestor. The multifactorial likelihood method by Goldgar, used to estimate the probability of the variant being causative, gave a ratio of 2,263,474:1 in favor of causality. Moreover, in silico modeling suggested that His1673-lacking BRCA1 protein may have a decreased ability to bind BARD1 and other related proteins. All six ovarian carcinomas and two out of four breast carcinomas available showed a loss of the BRCA1 wild-type allele, which in three out of four ovarian carcinomas analyzed by FISH was associated with duplication of the chromosome 17 containing the variant. Although the pathogenicity of the allele is strongly supported by the multifactorial ratio, we cannot exclude that p.His1673del is not itself deleterious, but is linked to another undetected mutation on the same ancestral allele.

Evaluation of Transvaginal Ultrasound plus CA-125 Measurement and Prophylactic Salpingo-Oophorectomy in Women at Different Risk Levels of Ovarian Cancer: The Modena Study Group Cohort Study

Objective: To evaluate the effectiveness of transvaginal ultrasound (TVU) and serum CA-125 measurement in women at different risk of developing ovarian cancer/fallopian tube cancer (OC/FTC) and the incidence of primary peritoneal cancer (PPC) after risk-reducing salpingo-oophorectomy (RRSO). Methods: Between 2002 and 2014, 661 women at different risk of OC/FTC/PPC due to a family history or BRCA1/2 gene mutation were offered TVU and CA-125 measurement or RRSO as prevention strategies. The detection rate of OC/FTC/PPC was evaluated, and the sensitivity and specificity for CA-125 measurement and TVU were calculated. Survival and event analysis was performed for diagnosed patients. Results: After a median follow-up of 112 months, 12 OC/FTC/PPC cases were detected (2.6/1,000 persons/year). The screening sensitivity was 70%, with 73% for BRCA carriers. Six (50%) of 12 cancers were stage I or II. Among 41 women who underwent RRSO, 2 BRCA1 carriers developed a PPC (4.9%). At 61-month follow-up, overall and event-free survival were 75 and 64%, respectively. Conclusions: The cancer detection rate in women with BRCA mutation or a strong family history supports the effectiveness of our surveillance program for early diagnosis. Screening for women at lower risk of OC/FTC is not recommended. A residual risk of PPC after RRSO remains for BRCA1 carriers.

Collective evidence supports neutrality of BRCA1 V1687I, a novel sequence variant in the conserved THV motif of the first BRCT repeat

Unambiguous classification of BRCA1 and BRCA2 variants of uncertain significance (VUS) is a challenging task that vexes health care providers and has profound implications for patients and their family members. Numerous VUS have been described to date, which await assessment of their functional, hence clinical, impact. As a result of a routine BRCA1/BRCA2 mutational screening, we identified a previously unreported BRCA1 sequence alteration [c.5178G>A (V1687I)] in a patient diagnosed with early onset triple negative breast cancer. The sequence alteration falls in the invariant THV motif of the BRCT domain. To investigate its significance, we applied an integrated approach that, in addition to genetic and histopathological data, included in silico analyses, comparative structural modeling and verification of BRCT-mediated interactions. In line with web-based algorithms that predicted the benign nature of BRCA1 V1687I, the three-dimensional model of the BRCA1 V1687I BRCT domain did not reveal any major structural changes relative to its wild-type counterpart, thus suggesting that BRCA1 V1687I has a negligible impact on both the local architecture and the overall stability of the protein. Consistently, the BRCA1 V1687I protein was properly expressed and localized to the nucleus, and it was still capable of binding three BRCT-interacting, DNA damage response, and repair partner proteins, namely BRIP1/FANCJ, CtIP, and Abraxas. Our collected evidence suggests that, although occurring in a highly conserved region, the BRCA1 V1687I variant is likely a benign sequence alteration.