Citations

Background Clinical classification of rare sequence changes identified in the breast cancer susceptibility genes BRCA1 and BRCA2 is essential for appropriate genetic counselling of individuals carrying these variants. We previously showed that variant BRCA1 c.5096G>A p.Arg1699Gln in the BRCA1 transcriptional transactivation domain demonstrated equivocal results from a series of functional assays, and proposed that this variant may confer low to moderate risk of cancer. Methods Measures of genetic risk (report of family history, segregation) were assessed for 68 BRCA1 c.5096G>A p.Arg1699Gln (R1699Q) families recruited through family cancer clinics, comparing results with 34 families carrying the previously classified pathogenic BRCA1 c.5095C>T p.Arg1699Trp (R1699W) mutation at the same residue, and to 243 breast cancer families with no BRCA1 pathogenic mutation (BRCA-X). Results Comparison of BRCA1 carrier prediction scores of probands using the BOADICEA risk prediction tool revealed that BRCA1 c.5096G>A p.Arg1699Gln variant carriers had family histories that were less ‘ BRCA1 -like’ than BRCA1 c.5095C>T p.Arg1699Trp mutation carriers (p<0.00001), but more ‘ BRCA1 -like’ than BRCA-X families (p=0.0004). Further, modified segregation analysis of the subset of 30 families with additional genotyping showed that BRCA1 c.5096G >A p.Arg1699Gln had reduced penetrance compared with the average truncating BRCA1 mutation penetrance (p=0.0002), with estimated cumulative risks to age 70 of breast or ovarian cancer of 24%. Conclusions Our results provide substantial evidence that the BRCA1 c.5096G>A p.Arg1699Gln (R1699Q) variant, demonstrating ambiguous functional deficiency across multiple assays, is associated with intermediate risk of breast and ovarian cancer, highlighting challenges for risk modelling and clinical management of patients of this and other potential moderate-risk variants.

Abstract Bladder cancer is the 4th most commonly diagnosed cancer in the United States. Because superficial bladder cancer (SBC) recurs in about 60% of cases, standard treatment involves tumor resection followed by intravesical therapies to prevent recurrence, as well as lifelong periodic cystoscopy. There is an urgent need for better intravesical therapies to prevent both the recurrence and progression of SBC. The Mammalian Target Of Rapamycin (mTOR) complex is upregulated in many bladder cancer tumors. We have targeted both the mTORc1 and mTORc2 complexes with drugs that inhibit both complexes. We used PP242 and a second inhibitor, OSI-027, which is currently in a phase I clinical trial for solid tumors (NCT00698243). Our in vitro model targets cell proliferation in three bladder cancer cell line (HT1376, T24 and UM-UC-3). Both drugs are effective in inhibiting the growth of bladder cancer cell lines with IC50 values between 0.6 and 18µM. In comparison with rapamycin, both drugs demonstrate effects on downstream targets of both the mTORc1 and mTORc2 pathways including 4EBP1 and pAkt. Receptor tyrosine kinases are another therapeutic target for bladder cancer. Lapatinib which targets EGFR and Her3, in combination with OSI-027 forms a highly synergistic treatment that inhibits bladder cancer cell line growth. Downstream molecular targets of the combination therapy, including the apoptosis markers PARP and caspase 3, were evaluated by Western blots. Our in vitro data suggests that a combination of dual mTOR inhibitors with RTK inhibitors may provide a novel effective therapeutic treatment for bladder cancer. Future studies of the in vivo efficacy of these drug combinations in a mouse model are planned. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 896. doi:1538-7445.AM2012-896