2009 Vienna - European Society of Human Genetics

Cancer genetics
the past and it is probably positioned in a hot spot point for mutations.
The two different haplotypes reflects diverse historical origins in the
east and west Castilla-León region.
P06.121
Detection and characterization of new large deletion of exon 3 in
the BRCA gene among a French breast cancer family.
D. Muller1 , E. Rouleau2 , I. Schultz1 , C. Andrieux2 , O. Caron3 , R. Lidereau2 , J.
Abecassis1 , J. Fricker1 ;
1 2 CRLCC P. Strauss, Strasbourg, France, CRLCC R. Huguenin, Inserm U735,
Saint Cloud, France, 3Hôpitaux Universitaires, Strasbourg, France.
Germ-line mutations in two genes, BRCA1 and BRCA2 genes, are
the major contributors to hereditary breast/ovarian cancer. Nowadays,
large rearrangements have been described regularly in BRCA1 with
approximately 10-15% of the mutations in this gene. In contrast, large
genomic rearrangements in the BRCA2 gene have been rarely reported.
During the comprehensive screening of breast/ovarian cancer families
for germ-line mutation in these genes, we detected a deletion of exon
3 in BRCA2 in a breast cancer family, using the QMPSF (quantitative
multiplex PCR of short fluorescent fragments) and confirmed by MLPA
(multiplex ligation-dependent probe amplification) methods for detection
of large genomic rearrangements. This mutation was characterized
by high-resolution oligonucleotide array-CGH technology which
estimated the size of the deleted region and helped to find the breakpoint.
Precise determination of the size and identification of the breakpoint
were obtained with a specific PCR and the deleted sequence
was different from previous reports. Moreover, analysis of transcripts
revealed the only skipping of exon 3. Since this deletion is in-frame,
the deleterious impact is largely discussed in the literature. Despite a
limited number of cases in this family, the segregation data seemed to
be consistent with a causal effect of the mutation.
In addition to conventional DNA diagnostic testing by sequencing,
familial breast cancer patients can benefit from searching for large
rearrangements in the BRCA2 gene. The in-frame deletion of exon
3 needs additional studies to investigate its contribution to hereditary
breast/ovarian cancer.
P06.122
BRCA1/2 screening results: Review of molecular data
concerning Portuguese high-risk breast/ovarian cancer families
P. M. Machado 1 , S. Santos 1 , S. Fragoso 1 , S. Bento 2 , P. Rodrigues 2 , A. Luís 2 , A.
Opinião 2 , F. Vaz 1,2 ;
1 Molecular Biology Department - Portuguese Institute of Oncology, Lisbon,
Portugal, 2 Breast Cancer Risk Evalution Clinic- Portuguese Institute of Oncology,
Lisbon, Portugal.
Introduction: Although BRCA1 and BRCA2 are the genes most frequently
involved in familial aggregation of breast/ovarian cancer, mutations
in other genes like TP53, PTEN, ATM, CHEK2 and PALB2 could
also cause breast cancer risks. Taken together, the known susceptibility
genes account for less than one third of breast cancer families
undergoing genetic testing while other gene defects remain to be discovered
[EMQN guidelines 2007].
Patients and methods: Review of all patients for whom BRCA1/2
screening is complete. All patients underwent pre and post-test counselling
and are pre-screened for the BRCA2 Portuguese founder mutation
[Machado et al, 2007]. Negative patients are further analysed by
CSCE and samples with a different pattern are sequenced. Previous to
the CSCE optimization, DNA samples were analysed by CSGE.
Results: Two hundred and forty nine families were fully screened for
BRCA1/2 mutations and 61 positive patients were detected (10 BRCA1
and 51 BRCA2 mutations, including 28 families with the founder mutation),
which corresponds to a 25% detection rate. The range of mutations
and sequence variants as well as their frequency in this set of
patients were analysed, allowing for a better characterization of the
breast/ovarian cancer high risk families from the Central and Southern
regions of Portugal. Depending on pedigree reanalysis BRCA1/2
negative families are being screened for other gene mutations (p53
and PTEN).
Conclusion: From 249 Portuguese high-risk families, 61 presented deleterious
BRCA mutations. As expected, several neutral or unknown
variants were also detected, posing a significant challenge for counselling.
P06.123
Identification and characterization of large genomic
rearrangements in BRCA , BRCA and CHEK genes
J. Del Valle 1 , M. Nadal 1 , L. Feliubadaló 1 , R. Cuesta 1 , E. Tornero 1 , M. Menéndez
1 , J. Brunet 2 , À. Teulé 2 , G. Capellá 1 , I. Blanco 2 , C. Lázaro 1 ;
1 Programa de Diagnòstic Molecular de Càncer Hereditari, Laboratori de Recerca
Translacional, Institut Català d’Oncologia-IDIBELL, Hospitalet de Llobregat,
Barcelona, Spain, Hospitalet de Llobregat, Spain, 2 Programa de Consell Genètic
en Càncer, Institut Català d’Oncologia, Hospitalet de Llobregat-IDIBELL
(AT, IB) and Girona- IdIBGi (JB), Hospitalet de Llobregat, Spain.
Large genomic rearrangements are estimated to account for about 5-
10% of all disease-causing mutations in BRCA1 and BRCA2 genes in
patients with hereditary breast and ovarian cancer syndrome (HBOC).
To screen for such rearrangements in patients with HBOC, and as a
first step in our genetic testing workflow, we use MRC-Holland Multiplex
Ligation-dependent Probe Amplification (MLPA). We have used
this technique in a set of 310 independent patients and we have detected
9 different copy number alterations corresponding to 3% of the
studied samples and about 15% of all identified mutations in BRCA1
and BRCA2 genes in our cohort. As commercial MLPA tests are not
suitable to determine the specific breakpoints or to define the exact
extension of the rearrangement, we have applied a set of different
complementary techniques in order to better characterize these genetic
alterations. We have used long-range PCR amplification, RNA
analysis, SNP array chips, not commercial MLPA probes and FISH
analysis to fully define the extent and mechanism of each of the identified
alterations. Briefly, in BRCA1 we have characterized 6 rearrangements:
deletion of E22, deletion of E9-E24, deletion of E16-E23, deletion
of E1-E13, deletion of E1-E2, duplication of E1-E2. In BRCA2 we
studied a deletion of E15-E16 and a deletion of E1-E24 and in CHEK2
we have identified a complete gene deletion. In addition, it is worth to
mention that MLPA demonstrated to be useful to identify point mutations
located within probe sequences.
P06.124
cost-effectiveness analysis of prophylaxis programme in women
with a family history of breast cancer and cHEK2*1100delc
heterozygosity in the Polish health-care system
E. Orlewska1 , J. Lubinski2 , C. Cybulski2 ;
1 2 Centre for Pharmacoeconomics, Warsaw, Poland, Pomeranian Medical University,
Szczecin, Poland.
Aim of the study: economic evaluation of prophylaxis programme starting
at 25 years old women with a family history of breast cancer and
CHEK2*1100delC heterozygosity versus no prophylaxis.
Methods: Cost-effectiveness analysis was perfomed using modelling
technique. Two cohorts were studied: without prophylaxis, and with
prophylaxis. Data on life expectancy, breast cancer risk, efficacy of
prophylaxis and medical costs were obtained from published literatures.
The cohort simulation started with 25-year-old women and
projected direct medical costs and outcomes over patients lifetimes.
Effectiveness was measured as life years gained (LYG). Only direct
medical costs (breast cancer prophylaxis and treatment of breast
cancer I-IV stages) were included, assessed from health-care payer
perspective and reported in PLN (1 EUR= 4.5 PLN in 2009). 5% and
3.5% discount rate was used for cost and effectiveness, respectively.
Sensitivity analyses to treatment patterns, efficacy of prophylaxis and
costs were performed.
Results: The total lifetime costs/patient were estimated to be 4453
PLN (discounted: 1318 PLN) in no prophylaxis arm and 5380 PLN
(discounted : 2135 PLN) in prophylaxis arm . The life expectancy generated
with prophylaxis was 75.43 vs. 70.5 for no prophylaxis (without
discounting) and 48.01 vs. 46.79 (discounted), respectively. This
results in ICER for prophylaxis of 187.7 PLN/LYG (without discounting)
and 672.7 PLN/LY (discounted). Results were robust to sensitivity
analyses.
Conclusion: Breast cancer prophylaxis programme for women with a
family history of breast cancer and CHEK2*1100delC heterozygosity
compared to no prophylaxis improves survival and is highly cost-effective
in the Polish health-care system.