Background: Inheritance of a mutation in either BRCA1 or BRCA2 accounts
for approximately 5% of all breast cancer cases, but varies by country.
Investigations into the contribution of BRCA mutations to breast cancer
incidence in Greece have been, for the most part, limited by small
sample sizes and by the use of cases selected for their family history
of cancer. The aim of the current study was to estimate BRCA mutation
frequencies in breast cancer patients unselected for family history.
Methods: To do so, we enrolled 127 unselected women with breast cancer
from the Alexandra Hospital in Athens, Greece, a large public hospital
in the city. Mutations in BRCA1 and BRCA2 were detected using a
combination of techniques and were confirmed by direct sequencing. Two
large genomic deletions were sought using mutationspecific assays. A
detailed family history of cancer was obtained from each patient.
Results: We were able to successfully complete testing on samples from
127 women. Among these, six mutations were identified (four in BRCA1 and
two in BRCA2) representing 4.7% of the total or 9.5% of cases
diagnosed before age forty. None of the mutation carriers had a family
history of breast or ovarian cancer. Three of the four BRCA1 mutations
were in exon 20: two were a G5331A mutation and the third was a 3.2 kb
deletion. The fourth BRCA1 mutation was the 3819delGTAAA in exon 11. The
two BRCA2 mutations were in exon 11 (3782del10 and 4512insT).
Conclusions: The G5331A mutation in BRCA1 appears to be a founder
mutation in the Greek population
