The Bahamas is a group of islands in the Caribbean with a high incidence of early onset breast cancer. In isolated populations, the identification of founder mutations in cancer predisposing genes may facilitate genetic testing and counseling. To date, six distinct BRCA1 mutations have been found in patients from cancer families from the Bahamas. The frequencies of these mutant alleles have not been measured in a large series of unselected breast cancer patients from Bahamas. We studied 214 Bahamian women with invasive breast cancer, unselected for age or family history of cancer. All patients were screened for six mutations in the BRCA1 gene that have previously been reported in cancer patients from the Bahamas. A mutation was identified in 49 of the 214 breast cancer patients (23%). The mutation frequency was particularly high in women diagnosed before age 50 (33%) in women with a first-degree relative with breast or ovarian cancer (41%) and in women with bilateral breast cancer (58%). Approximately 23% of unselected cases of breast cancer in the Bahamian population are attributable to a founder mutation in the BRCA1 gene-this is the highest reported mutation prevalence for any country studied to date. Genetic testing for these mutations is advisable for all women diagnosed with breast cancer in the Bahamas.

We sought to identify the full range of founder mutations in BRCA1 and BRCA2 in the Bahamas and to estimate the proportion of all BRCA1 and BRCA2 mutations that are accounted for by founder mutations. We studied 214 Bahamian women with invasive breast cancer, unselected for age or family history. A founder mutation had previously been identified in 49 patients. We conducted full sequencing of the BRCA1 and BRCA2 genes and multiplex ligation-dependent probe amplification (MLPA) for 156 patients. A novel founder mutation in BRCA2 (exon 17 818delA) was seen in four different patients and five other unique mutations in BRCA1 and BRCA2, including a large deletion (exons 8-9) in BRCA1. In total, a mutation was seen in 58 of the 214 patients (27%); 92% of carriers carried one of the seven founder mutations. Approximately 27% of unselected cases of breast cancer in the Bahamian population are attributable to a mutation in BRCA1 or BRCA2, a prevalence which far exceeds that of any other country. The majority of women who carry a mutation in the Bahamas, carry one of the seven founder mutations, making it possible to offer genetic testing to all women at risk for breast cancer in the Bahamas.

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1089 Background: The addition of bevacizumab (B) to paclitaxel (P) results in a significant improvement in PFS in pts with metastatic breast cancer (MBC) (Miller K, et al. New Engl J Med 2007). A randomized Phase II trial examining the efficacy and safety of adding gemcitabine (G) to the PB doublet has completed enrollment. Reported here are preliminary efficacy and safety results. Methods: This is a US, multicenter, randomized, superiority trial. Eligible pts have locally advanced or metastatic breast cancer, ECOG PS 0 or 1, and no prior cytotoxic therapy for metastatic disease. Prior adjuvant or neoadjuvant treatment with a taxane or endocrine therapy is allowed. Pts are randomized to receive P 90 mg/m2 on Days 1, 8, and 15, followed by B 10 mg/kg on Days 1 and 15 of a 28-day cycle, or the same regimen plus G 1,500 mg/m2 on Days 1 and 15. Primary endpoint is response rate according to RECIST criteria. Results: Between May 2006 and February 2008, 189 women were randomized to treatment. The table below summarizes currently available results. Grades 1–2 alopecia occurred in 28% of pts in the PB arm and in 38% of pts in the PB+G arm. One pt (2%) in the PB arm experienced a Grade 3 nosebleed. Grades 3 and 4 thrombotic events occurred respectively in 0% and 2% of pts in the PB arm, and in 3% and 2% of pts in the PB+G arm. Four pts (7%) in the PB arm and 3 pts (5%) in the PB+G arm discontinued due to treatment-related AEs. Three on-study deaths have occurred, none deemed related to study treatment. Conclusions: Study follow-up is ongoing. Full results will be available at the time of the meeting. Therapy with PB ± G is feasible and does not appear to be associated with significant bleeding or thrombotic events. As expected, the addition of G to the PB doublet appears to increase the incidence of neutropenia in pts with MBC. [Table: see text] [Table: see text]

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