[Prevalence of the 185Ag deletion of the BRCA1 gene in Chilean women with breast neoplasm].

The most important identified pathogenic factor for breast cancer is the presence of mutations in BRCA1 gene. These are associated with familial breast cancer in up to 80% of cases. The most frequent mutation of BRCA1 gene in Caucasian populations is the exon 2 185AG deletion.,To study the presence of 185AG deletion in Chilean women with sporadic or familial breast cancer.,We studied 15 women with familial breast 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 for the native form that renders a 118 base pairs product and one for the deletion that renders a 170 base pairs product, both with a respective 280 base pairs internal control.,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 groups, the product of the amplification was the 118 base pairs band, that corresponds to the native form of BRCA1 gene. The polymerase chain reaction was optimized for a duration of 90 minutes.,185AG deletion of BRCA1 gene was not detected in this group of Chilean women with sporadic or familial breast cancer.