Citations

Abstract Background: A recent association study identified a common variant (rs9790517) at 4q24 to be associated with breast cancer risk. Independent association signals and potential functional variants in this locus have not been explored. Methods: We conducted a fine-mapping analysis in 55,540 breast cancer cases and 51,168 controls from the Breast Cancer Association Consortium. Results: Conditional analyses identified two independent association signals among women of European ancestry, represented by rs9790517 [conditional P = 2.51 × 10−4; OR, 1.04; 95% confidence interval (CI), 1.02–1.07] and rs77928427 (P = 1.86 × 10−4; OR, 1.04; 95% CI, 1.02–1.07). Functional annotation using data from the Encyclopedia of DNA Elements (ENCODE) project revealed two putative functional variants, rs62331150 and rs73838678 in linkage disequilibrium (LD) with rs9790517 (r2 ≥ 0.90) residing in the active promoter or enhancer, respectively, of the nearest gene, TET2. Both variants are located in DNase I hypersensitivity and transcription factor–binding sites. Using data from both The Cancer Genome Atlas (TCGA) and Molecular Taxonomy of Breast Cancer International Consortium (METABRIC), we showed that rs62331150 was associated with level of expression of TET2 in breast normal and tumor tissue. Conclusion: Our study identified two independent association signals at 4q24 in relation to breast cancer risk and suggested that observed association in this locus may be mediated through the regulation of TET2. Impact: Fine-mapping study with large sample size warranted for identification of independent loci for breast cancer risk. Cancer Epidemiol Biomarkers Prev; 24(11); 1680–91. ©2015 AACR.

ABSTRACTNeither breakpoints (BPs) nor epidemiological cutoff values (ECVs) have been established forCandidaspp. with anidulafungin, caspofungin, and micafungin when using the Sensititre YeastOne (SYO) broth dilution colorimetric method. In addition, reference caspofungin MICs have so far proven to be unreliable.Candidaspecies wild-type (WT) MIC distributions (for microorganisms in a species/drug combination with no detectable phenotypic resistance) were established for 6,007Candida albicans, 186C. dubliniensis, 3,188C. glabratacomplex, 119C. guilliermondii, 493C. krusei, 205C. lusitaniae, 3,136C. parapsilosiscomplex, and 1,016C. tropicalisisolates. SYO MIC data gathered from 38 laboratories in Australia, Canada, Europe, Mexico, New Zealand, South Africa, and the United States were pooled to statistically define SYO ECVs. ECVs for anidulafungin, caspofungin, and micafungin encompassing ≥97.5% of the statistically modeled population were, respectively, 0.12, 0.25, and 0.06 μg/ml forC. albicans, 0.12, 0.25, and 0.03 μg/ml forC. glabratacomplex, 4, 2, and 4 μg/ml forC. parapsilosiscomplex, 0.5, 0.25, and 0.06 μg/ml forC. tropicalis, 0.25, 1, and 0.25 μg/ml forC. krusei, 0.25, 1, and 0.12 μg/ml forC. lusitaniae, 4, 2, and 2 μg/ml forC. guilliermondii, and 0.25, 0.25, and 0.12 μg/ml forC. dubliniensis. Species-specific SYO ECVs for anidulafungin, caspofungin, and micafungin correctly classified 72 (88.9%), 74 (91.4%), 76 (93.8%), respectively, of 81Candidaisolates with identifiedfksmutations. SYO ECVs may aid in detecting non-WT isolates with reduced susceptibility to anidulafungin, micafungin, and especially caspofungin, since testing the susceptibilities ofCandidaspp. to caspofungin by reference methodologies is not recommended.

Abstract About 25% of breast carcinomas are characterized by over-expression and/or amplification of the HER2 receptor, one of four members of the HER family of receptor tyrosine kinases. The strong correlation between HER2 levels/activity with more aggressive breast cancer disease, poor prognosis as well as resistance to chemo- and endocrine therapies made it a preferred target for anti-cancer therapy. However, current treatment strategies are only partially effective and the majority of breast cancer patients who initially respond favorably rapidly develop resistance to treatments for still not fully understood reasons. Thus, novel strategies/agents are in need. Structural analyses revealed that sub-domain III in the extracellular domain (ECD) of the HER family members is responsible for dimerization. We hypothesized that disrupting the dimerization loop in the HER2-ECD sub-domain III would ultimately convert HER2 to a non-functional receptor with diminished transforming capacity. To this end, we generated a series of HER2-ECD deletion mutants located in sub-domain III and assessed their oncogenic potential compared to the HER2-wild type (WT) after their expression in MCF10A cells. Importantly, a small deletion (16 amino acids) of the HER2 extracellular domain (named HER2Δ6) abolished its homo- and hetero-dimerization and profoundly affected HER2-catalyzed activation of the HER network. Moreover, this mutant was not able to transform MCF10 cells as it failed to promote anchorage-independent growth and interfered with the activation/Tyr phosphorylation of HER1, HER2 and HER3. Compared to HER2-WT-expressing cells, the HER2α6 mutant proved to be even more effective in inhibiting the oncogenic properties of the receptor than the current drugs of choice such as Trastuzumab and Pertuzumab alone or in combination. In addition, while expression of HER2-WT conferred resistance of MCF10A cells to Paclitaxel, the HER2Δ6 variant failed to do so. To determine the molecular mechanisms underlying this behavior, we assessed the mutant and WT expressing cells lines morphologically and biochemically and demonstrated that the HER2Δ6 is absent from the plasma membrane (PM) in MCF10A cells. Interestingly, we found that the mutant receptor displayed an intracellular trafficking defect and was trapped in the endoplasmic reticulum (ER). Our results reveal that the HER2-ECD bears an essential “activating” region that is indispensable for HER2-mediated oncogenic transformation. Targeting and eliminating this “activating” element in HER2 seems to provide a strong innovative approach for developing a valuable novel anti-HER2 therapeutic drug that would specifically benefit patients with HER2 positive tumors resistant to current therapies. Citation Format: Barbara Schroeder, Ghiara Lugo, Javier Menendez, Ingrid Espinoza, Ruth Lupu. Identification of a key region in the HER2 subdomain III required for transformation capability. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 133. doi:10.1158/1538-7445.AM2015-133

Diabetic ketoacidosis is a life-threatening acute metabolic complication of uncontrolled diabetes. Severe cases of DKA (pH ≤ 7.00, bicarbonate level ≤ 10.0, anion gap > 12, positive ketones, and altered mental status) are commonly encountered in patients with type 1 diabetes and are thought to carry an ominous prognosis. There is not enough information on the clinical course of severely acidotic type 2 diabetes (pH ≤ 6.9) patients with DKA, possibly because this condition is rarely seen in developed countries. In this series, we present 18 patients with type 2 diabetes, DKA, and a pH ≤ 6.9 that presented to a tertiary university hospital over the past 11 years. The objective was to describe their clinical characteristics, the triggering cause, and emphasis on treatment, evolution, and outcomes. The majority of the patients were female (61%). Mean age was 40.66 years (23–59). The patients had been first diagnosed with type 2 diabetes on average 5.27 ± 3.12 years before admission. Glutamic acid decarboxylase (GAD65) antibodies were negative in all patients. The origin of DKA could be attributed to two main causes: treatment omission in 8 (44.4%) patients and infections in 7 (38.8%) patients. The most common symptoms described were general malaise, dyspnea, altered mental status, and abdominal pain. Mean serum glucose on admission was 613.8 ± 114.5 mg/dL. Mean venous pH was 6.84 ± 0.03 with an anion gap of 30.3 ± 2.9 and a venous HCO3level of 3.62 ± 1.35 mmol/L. All patients had acute renal failure on admission, with a mean serum creatinine of 1.57 ± 0.35 mg/dL compared to 0.55 ± 0.21 mg/dL at discharge. All patients received regular insulin infusion, aggressive fluid repletion, and 12 patients (66%) received bicarbonate infusion. Mean total insulin infusion dose was 181.7 ± 90.4 U (on average 0.14 ± 0.05 U/Kg/h). Mean time on infusion was 24.4 ± 12.6 hours. We recorded no mortality in this case series. Mean in-hospital stay was 5.0 ± 4.1 days. In conclusion, very severe DKA in type 2 diabetes is not uncommon in our population, shares many features with non-very-severe cases of DKA (bicarbonate therapy did not make a difference in mortality), and can be managed following standard published or institutional guidelines.

Abstract The HER2 receptor is over-expressed in about 25% of breast carcinomas and correlates with more aggressive breast cancer disease, poor prognosis as well as resistance to chemo- and endocrine therapies. The strong correlation between HER2 levels/activity and the malignancy of the disease made it a preferred target for anti-cancer therapy. For example, Trastuzumab, which targets HER2 homo-dimerization and Pertuzumab, which interferes with HER2 hetero-dimerization, are in clinical use. Unfortunately, Trastuzumab monotherapy is only partially effective and the majority of breast cancer patients who initially respond to Trastuzumab rapidly develop resistance to the drug. Thus, novel strategies/agents are in need, especially drugs that prevent hetero-dimerization with other HER family members. Structural analyses revealed that sub-domain III in the extracellular domain (ECD) of the HER family members is responsible for dimerization. Therefore, we hypothesized that disabling the dimerization loop in the HER2-ECD sub-domain III would ultimately convert HER2 to a non-functional receptor. Therefore, we introduced a series of deletions in the HER2-ECD sub-domain III and determined their oncogenic properties compared to HER2wt expressing cells. Importantly, a small deletion (16 amino acids) of the HER2 extracellular domain (named HER2Δ6) abolished its homo- and hetero-dimerization and profoundly affected HER2-catalyzed activation of the HER network, both in the context of HER2 over-expression and ligand-induced trans-activation of HER2. Expression of the HER2Δ6 variant failed to promote anchorage-independent growth and interfered with the activation/Tyr phosphorylation of HER1, HER2 and HER3. Moreover, this mutant failed to promote resistance to Paclitaxel treatment in HER2-overexpressing breast cancer cells. To determine the molecular mechanisms underlying this behavior, we assessed the mutant and wt expressing cells lines morphologically and biochemically and demonstrated that the HER2Δ6 is absent from the plasma membrane (PM), most likely due to a intracellular trafficking defect that mistargets the receptor to or traps it in an endomembrane compartment. Compared to HER2wt-expressing cells, the HER2Δ6 mutant proves to be even more effective in inhibiting the oncogenic properties of the receptor than the current drugs of choice such as Trastuzumab, Pertuzumab and Cetuximab alone or in combination as measured by anchorage-independent growth. These findings reveal that the HER2-ECD bears an essential "activating" region that is indispensable for HER2 homo-and heterodimerization. Elimination of this "activating" element in HER2 seems to recapitulate and greatly improve the combined actions of Trastuzumab and Pertuzumab. These findings offer a strong rationale for developing this peptide sequence into a valuable anti-HER2 therapeutic drug. Citation Format: Barbara Schroeder, Menendez Javier, Espinoza Ingrid, Lupu Ruth. Blocking a key region in the HER2 subdomain III inhibits the HER2-network in patients with resistance to HER2-targeted therapy [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P6-07-08.

Abstract Background: Etirinotecan pegol (EP) is the first long-acting topoisomerase 1-inhibitor providing sustained level of active metabolite that concentrate in the tumor for an entire chemotherapy cycle. In a Phase 2 study (Lancet Oncology 2013), EP demonstrated a 29% overall response rate in patients with metastatic breast cancer, leading to the Phase 3 global BEACON study in this population. Detection of circulating tumor cells (CTCs) using immunomagnetic EpCAM-based methods have been conceptually accepted as a "liquid tumor biopsy". To circumvent the limited recovery of CTCs these methods provide for molecular profiling applications, we isolated CTCs based on an antibody-independent, continuous flow dielectrophoresis (DEP) technology (ApoStream®). We developed quantitative multiplex immunofluorescent assays for target-specific pharmacodynamics (PD) biomarkers for EP in CTCs isolated pre- and post-treatment. Here we present the distribution of the PD biomarkers in CTC samples collected from BEACON patients. Methods: Donation of blood samples for CTC analysis was voluntary. BEACON patients participating in the substudy had serial (pre-dose, Cycle 2 Day 1, Cycle 4 Day 1, End of Treatment) 7.5-mL whole blood samples drawn in EDTA tubes and shipped ambient to ApoCell (Houston, TX) within 96 hrs for processing. PBMCs were separated by Ficoll® gradient, and CTCs were isolated using ApoStream® technology. Isolated cells were deposited on three slides and stained for DAPI, CD45, and cytokeratin markers, as well as 2-3 of the seven PD markers, and analyzed by iCys® laser scanning cytometer equipped with image analysis software. CTC count, mean fluorescence intensity (MFI) of PD biomarkers, and % marker-positive cells were analyzed for their distribution. Results: 75% of the 852 BEACON patients participated in the CTC substudy, yielding 649 pre-treatment CTC samples. As of Mar14, 538 Cycle 2 Day 1, 281 Cycle 4 Day 1, and 394 End of Treatment samples were collected. 98% of pre-treatment blood samples were successfully processed. 97% had detectable CTCs, with a median of 504 CTCs (interquartile range: 128-1432). PD markers could be analyzed in 83-92% of samples after implementing a minimum requirement of 10 CTCs analyzed. Staining was positive for Top1, Top2, μH2Ax, Rad51, ABCG2, Ki67, and TUNEL in 82%, 71%, 14%, 30%, 20%, 56%, and 94% of samples, respectively. Percent of marker-positive cells varied from 0.2-69%, with 6- to 37-fold interquartile ranges. Median MFI in these cells varied between 25x103 and 100x103, with 1.2- to 1.6-fold interquartile ranges. Conclusions: CTC collection was successfully incorporated into the BEACON study, with 75% patient participation. CTC detection rate using ApoStream® was high, permitting evaluation of biomarkers at baseline and over time. EP target-specific PD biomarkers can be measured in CTCs isolated from patients participating in BEACON and will be assessed for their potential to predict clinical response. Final BEACON efficacy and safety results are expected in early 2015, which will allow further analysis of CTCs with patient outcome (response, PFS, OS) and change in CTCs at time of progression. Citation Format: Edith A Perez, Katie Caygill, Alison L Hannah, Javier Cortes, Ahmad Awada, Joyce O'Shaughnessy, Christopher Twelves, Hope Rugo, Seock-Ah Im, Kenna Anderes, Darren W Davis, Ute Hoch. Etirinotecan pegol target-specific pharmacodynamic biomarkers in circulating tumor cells from patients with metastatic breast cancer in the phase 3 BEACON study [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P3-10-03.