Prevalence of BRCA1 gene 185AG deletion in Chilean women with breast cancer

Background: The most important identified pathogenic factor for breast canc er is the presence of mutations in BRCA1 gene. These are associated wit fam ilial breast cancer in up to 80% of cases. The most frequent mutation of BR CA1 gene in Caucasian populations is the exon 2 185AG deletion. Aim: To stu dy the presence of 185AG deletion in Chilean women with sporadic or familia l breast cancer. Patients and methods: We studied 15 women with familial br east cancer; in whom at least one close relative was affected, and 40 women with sporadic breast cancer. In genomic DNA obtained from a blood sample, an allele specific polymerase chain reaction was done. This reaction allows the identification of 185AG deletion and uses two pairs of primers. One fo r the native form that renders a 118 base pairs product and one for the del etion that renders a 170 base pairs product, both with a respective 280 bas e pairs internal control. Results: The diagnosis of breast cancer was done at 40+/-5 and 65+/-10 years old in women with familial and sporadic breast cancer, respectively. In none of the samples, the amplification of the 170 base pairs band that corresponds to 185AG deletion, was obtained. In both g roups, the product of the amplification was the 118 base pairs band, that c orresponds to the native form of BRCA1 gene. The polymerase chain reaction was optimized for a duration of 90 minutes. Conclusions: 185AG deletion of BRCA1 gene was not detected in this group of Chilean women with sporadic or familia breast cancer.