Overall survival and clinical characteristics of BRCA germline/somatic cholangiocarcinoma (CCA).

244 Background: Biliary tract cancers (BTC) exhibit a diverse and high frequency of actionable mutations detectable using next generation sequencing (NGS). The Breast Cancer Linkage Consortium reported that BRCA2 mutation carriers are at increased risk for BTC with estimated relative risk of 4.97, (95% CI = 1. 50-16.52). The purpose of this study was to evaluate the clinical characteristics of germline/somatic BRCA1/2mutations in CCA patients. Methods: Multi-center retrospective analysis of patients with germline/somatic BRCA1/2- associated CCA diagnosed between January 2000 and December 2013. Cases were identified from clinical databases at participating institutions. Data including demographics, clinical history, surgical procedures and systemic chemotherapy or radiation were extracted from patient records. Results: Overall, we identified 18 cases including 5 carriers of germline BRCA1/2 mutations (4 BRCA2; 1 BRCA1) and 13 harboring somatic mutations (7 BRCA1; 6 BRCA2) using a NGS panel testing tumor for 'actionable' mutations. One patient presented with two different somatic mutations in the BRCA2gene. Mean age at diagnosis was 60 years (range 36-75), male: females (61.2% vs 38.8%, respectively). Stage at diagnosis: I (n = 4), II (n = 3), III (n = 3) and IV (n = 8). Six patients had extrahepatic CAA; twelve patients had intrahepatic CCA. Prior therapy in 13 patients included platinum-based therapy with one patient receiving prior olaparib. Median overall survival for patients with stage I/II is 34.7 months (95% CI, 7.06-62.9) and for stages III/IV is 25 months (95% CI, 12.02-35.84). Conclusions: BRCA associated CCA may have an enhanced therapeutic sensitivity to DNA damaging agents. This needs confirmation in a larger cohort of patients.

027.Mapping novel breast cancer susceptibility genes by linkage analysis of Australian multiple case kindreds

We have been using the resources of the Kathleen Cuningham Foundation Consortium for Research into Familial Breast Cancer (kConFab) and of the Australian Breast Cancer Family Study (ABCFS) to identify kindreds suitable for mapping high penetrance breast cancer susceptibility loci other than BRCA1 and BRCA2. A 10 cM genomewide search was carried out in 40 families in which BRCA1 and BRCA2 mutations had been excluded with high probability. The highest LOD score under heterogeneity (HLOD) was 2.16 (non-parametric LOD 1.83, P = 0.04) at the 11p telomere; several other regions with HLODs = 1.5–2.0 also merited investigation using fine mapping but have so far neither been confirmed or rejected by these analyses. Subsets based on age of onset and presence of other cancers correlated to some extent with particular linkage peaks and several regions (notably 2q and 13q) corresponded to areas of suggestive linkage reported recently in more limited studies of other cohorts. A large collaborative analysis of these data together with those from similar studies undertaken by members of the international Breast Cancer Linkage Consortium (BCLC) is under way. It is therefore likely that further major breast cancer susceptibility loci will be localised in the near future. The complementarity of these studies with genetic association, candidate gene and tumour-based approaches will be discussed.