Citations

Background: Peripheral nerve blocks (PNBs) have the potential to reduce postoperative pain. The use of ultrasound (US) to guide PNBs may be more beneficial than nerve stimulation (NS); however, very few studies have studied this technique in children. The objective of this study was to compare postoperative pain control in pediatric patients who had general anesthesia (GA) alone compared with those who had PNB performed by NS, or PNB with both NS and US guidance. Our hypothesis was that compared with NS, the US-guided PNB would result in reduced postoperative pain and opioid use, and that both PNB conditions would have improved outcomes compared with GA. Methods: A retrospective chart review of foot and ankle surgery included 103 patients who were stratified into 3 groups: GA, PNB with NS, and PNB with NS and US. Pain levels were measured with visual pain scales at 2, 4, 6, 8, 12, and 24 hours postoperatively. Days of hospitalization, morphine and oxycodone use by weight, and time to first PRN opioid use were also recorded. A repeated measure analysis of variance was used to compare the groups, and the proportion of patients who reported a visual analog scale score of 0 was calculated for each time point. Results: There were no significant differences in pain levels between groups for the first 12 hours, but the US group had higher pain levels at 24 hours. Both US and NS groups had a longer time to PRN opioid use and used significantly less morphine compared with GA. The US group had a significantly greater proportion of pain-free patients than the other 2 groups for the first 6 hours. Conclusions: The use of US guidance is beneficial in postoperative pain control. Both US-guided and NS-guided PNB are preferable to GA alone for lower extremity orthopaedic surgery in the pediatric population. Level of Evidence: III, retrospective comparative study.

Abstract Purpose: Mammographic breast density is an established and strong risk factor for breast cancer. Recently, a number of common genetic susceptibility loci have been identified as risk factors for breast cancer. We present the first report on the relative contribution of 76 validated breast cancer susceptibility loci, in the context of a polygenic risk score (PRS), to the breast density and breast cancer association. We also examine whether the PRS improves prediction of the Breast Cancer Surveillance Consortium (BCSC) 5-year risk model above and beyond breast density and clinical factors included in the model. Methods: The study population included 1643 cases and 2397 controls from three independent epidemiologic studies: the Mayo Mammography Health Study (MMHS), the Mayo Clinic Breast Cancer Study (MCBCS), and the Bavarian Breast Cancer Cases and Control Study (BBCC). Data collected on patients in each of the studies included clinical risk factor, BI-RADS breast density [a) almost entirely fat; b) scattered fibroglandular densities; c) heterogeneously dense; and d) extremely dense] and genotypes for the 76 breast cancer susceptibility loci known at the time of the study. We formed a PRS from the reported per-SNP odds ratios (OR) for 76 known breast cancer susceptibility loci, and evaluated whether BI-RADS density and the PRS were independent risk factors for breast cancer, when adjusted for age, 1/BMI and study. We also incorporated the PRS (OR) into the BCSC 5-year risk model and estimated 5-year risk for the MMHS nested case-control study of 339 invasive cases, 765 controls. Results: BI-RADS density (p<0.0001) and PRS (p<0.0001) were independent risk factors for breast cancer that together showed greater discrimination of risk (AUC=0.69) than density (AUC=0.66; ΔAUC=0.029) or PRS score alone (AUC=0.68; ΔAUC=0.013; p<0.001). Relative to those with scattered fibroglandular densities and average (2nd quartile) PRS, women with extremely dense breasts and in the highest PRS quartile, had a 2.7 fold (95%CI: 1.7-4.1) increased risk of breast cancer, while those with fatty breasts and in the lowest PRS quartile had a reduced risk (OR=0.30, 95%CI: 0.18-0.51). Incorporation of the PRS into the BCSC risk model improved discrimination (ΔAUC=0.031, p=0.001), for a net reclassification improvement of 20% (95%CI: 11%-28%), split equally among cases (9%) and controls (11%). Conclusion: BI-RADS density and the PRS are both important risk factors for breast cancer that can be included in breast cancer risk models to improve prediction of this disease. Using these models to identify high and low-risk risk groups will facilitate improved tailored screening and primary prevention interventions. Citation Format: Celine M. Vachon, V. Shane Pankratz, Christopher G. Scott, Lothar Haeberle, Elad Ziv, Matthew R. Jensen, Kathleen R. Brandt, Dana H. Whaley, Janet E. Olson, Katharina Heusinger, Carolin C. Hack, Sebastian M. Jud, Matthias W. Beckmann, Jeffrey A. Tice, Kristen S. Purrington, Thomas A. Sellers, Karla Kerlikowske, Peter A. Fasching, Fergus J. Couch. The contribution of common breast cancer susceptibility loci to the breast density and breast cancer association and the Breast Cancer Surveillance Consortium (BCSC) risk model. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 940. doi:10.1158/1538-7445.AM2014-940

Abstract Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal forms of human cancer, due in large part to a high incidence of metastasis and resistance to conventional chemotherapies. As such, new therapies are needed to halt the metastatic process. The proto-oncogene Vav1 is ectopically expressed in over half of human pancreatic cancers, and its expression correlates with a poor prognosis in humans and promotes survival and transformation in isolated tumor cells. We have found that Vav1, through its GEF activity towards Rac1, also potently induces migration by pancreatic tumor cells. In addition, Vav1 also signals through Cdc42 to drive the formation of invadopodia and matrix degradation, which also promotes tumor cell invasion. Importantly, the activation of Vav1 circumvents the requirement for active Src in this process. Because Vav1 is ectopically expressed in pancreatic cancers and is a potent regulator of tumor cell survival, proliferation, and invasive migration, it could provide a specific therapeutic target for these tumors. Recently, the anti-inflammatory agent azathioprine was described as an inhibitor of Vav1/Rac1 activity in hematopoietic cells. Therefore, we hypothesized that azathioprine could also inhibit the Vav1-driven processes of proliferation and invasion in pancreatic tumor cells. Indeed, we have determined that azathioprine treatment of cultured human PDAC cells reduces viability and proliferation. Further, similar to siRNA-mediated depletion of Vav1, azathioprine treatment reduces cell migration, as well as the matrix degradation required for invasion. Vav1-expressing tumor cells were more sensitive to azathioprine than Vav1-negative cells, supporting the premise that the inhibitory effects of azathioprine are mediated through Vav1. Finally, azathioprine also reduces metastasis in a xenograft model of pancreatic cancer. Taken together, these data uncover a role for aberrantly expressed Vav1 in regulation of the cytoskeletal machinery required for migration and invasion, and in the promotion and metastasis of pancreatic cancer. Even with the expression of multiple Rho family GEFs, tumor cells that upregulate Vav1 have become dependent upon this exchange factor, implicating Vav1 as a potent node for therapeutic intervention. Supported by R01 CA104125 and R03 CA155778 to M.A.M. Citation Format: Gina L. Razidlo, Christopher Magnine, Arthur C. Sletten, Rachel M. Hurley, Mark A. McNiven. Attenuation of pancreatic cancer cell migration and invasion through a targeted inhibition of the Rac GEF Vav1. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 4026. doi:10.1158/1538-7445.AM2014-4026

Abstract Background. We recently identified an in-frame ESR1 translocation in a tumor and PDX pair from a patient with endocrine therapy resistant advanced disease. The fusion gene preserved the N-terminal 365aa of ESR1 containing the intact activation function 1 (AF1), DNA-binding domain (DBD) and hinge, followed by the C-terminal transactivation domain of YAP1. The ESR1-365>YAP1 fusion drove estrogen-independent and anti-estrogen-resistant tumor cell growth (Cell Reports 4:1116, 2013). We therefore sought to further investigate the role of ESR1 fusion genes in breast cancer. Methods. 711 cases from TCGA, 82 ER+ cases from neoadjuvant endocrine therapy trials and 25 ER+ systemic relapse samples were screened for fusion genes using RNAseq. Fusion genes involving ESR1 were subsequently assayed for estrogen response element (ERE)-mediated transcriptional activity and ability to drive estradiol independent breast cancer cell growth. Results. Multiple ESR1 fusions were identified in mostly luminal B cancers. ESR1 fusions resulted most frequently from rearrangements involving another gene on Chromosome (Chr) 6 but also fusions with genes on other chromosomes. The fusions involving partners on Chr6 that retained an intact N terminal AF1 and DNA binding domain (DBD) of ESR1 (≥1-253aa) included an Out-of-Frame (OF) fusion event with CCDC170 (a gene immediately centromeric to ESR1), POLH (in-frame or IF), AKAP12 (IF), PCMT1 (OF), SYNE1 (OF) and GPR126 (OF). Also identified were inter-chromosomal translocations involving Chr12p-NOP2 (IF) and ChrX-PCDH11X (IF) and Chr7q-AKR1D1 (OF). The ESR1 fusions with transcriptional potential (because of a retained DNA binding domain) included variable 5’ ESR1 exons that preserved 253aa, 365aa, 412aa or 458aa of ESR1 sequence: in all cases disrupting ligand binding though loss of C terminal sequence. The effect of the IF and OF 3’ sequences on the transcriptional activity of the relevant ESR1 fragment was highly variable. The most transcriptionally active fusion (more active than the relevant ESR1 fragment alone) was the ESR1-365>YAP1 as well as ESR1-365>PCDH11X and ESR1-253>CCDC170. This is remarkable since PCDH11X is not considered a transcription factor and the CCDC170 sequence was OF – in both cases suggesting the activity of the fusion was due to "neomorphic" properties. Two fusions, NOP2 and POLH were inactive in the ERE reporter assay, yet both stimulated estradiol independent growth. In these cases we suggest that the ESR1 locus can function as a "promoter trap" which allows the identification of genes with previously unknown functions in endocrine therapy resistance. Conclusions: In luminal-type breast cancer the ESR1 gene was fused to multiple 3’ partners with remarkably heterogeneous functions. The two most transcriptionally active, ESR1-365>YAP1 and ESR1-365>PCDH11X, were both identified in endocrine therapy refractory advanced disease – suggesting a role in fatal disease progression. Citation Format: Jieya Shao, Jin Zhang, Robert J Crowder, Rodrigo Goncalves, Chanpheng Phommaly, Breast AWG and Network, Charles M Perou, Christopher A Maher, E Aubrey Thompson, Matthew J Ellis. ESR1 gene fusions implicated in endocrine therapy resistance of ER+ breast cancer [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 PD6-4.

Abstract Background: Mammographic breast density (MBD) reflects the proportion of fibroglandular tissue in the breast, and is an established risk factor for breast cancer. Benign breast disease (BBD) is also a known risk factor for breast cancer. We previously showed an association between lobular involution (physiologic atrophy) and MBD in a large cohort study of women with BBD. We performed a comprehensive evaluation of the association of histologic features of BBD with MBD. Methods: The Mayo BBD cohort includes women, 18 to 85 years, who were diagnosed with BBD at Mayo Clinic in Rochester, MN between 01/01/1967 and 12/31/1991. For this study, we included women who had a mammogram within 6 months of BBD diagnosis, and diagnosed with BBD between 1985 and 1991 when parenchymal pattern of breast density was clinically recorded. Risk factor information such as age, and body mass index (BMI) was collected from medical records. Parenchymal pattern, assessed clinically and previously used in multiple studies of MBD and risk, classified breast density based on extent and type of density, into four categories: N1 (non-dense, no ducts visible); P1 (ductal prominence occupying <25% breast); P2 (prominent ductal pattern occupying >25% of the breast; DY (homogenous plaque-like areas of density). All assessments of benign breast tissue were performed by expert breast pathologists blinded to both MBD and BBD reports. Histologic characteristics included overall impression (non-proliferative disease (NPD), proliferative disease without atypia (PDWA), and atypical hyperplasia (AH)), proportion of normal lobules that were involuted (no (0%), partial (1 to 74%), or complete (≥75%)), type of AH (ADH or ALH), ductal and lobular hyperplasia, calcifications, sclerosing adenosis, columnar alteration, cyst, fibroadenoma, marked fibrosis, intra-ductal papilloma, radial scar (number and size), duct ectasia, and mucocele like tumors. Associations of parenchymal pattern with BBD characteristics were examined using multicategorical nominal logistic regression models. We first examined associations after adjustment for age and BMI. All variables statistically significant (p<0.05) in these models were then simultaneously included in a fully-adjusted model. Results: Of 2,257 women in the study, 14% were <40 years old, 52.7% between 40- 59 years, and 32.9% were ≥60 years. In this sample, 55.2% of women had NPD, 36% had PDWA, and AH in 8.8%. MBD was classified as N1 in 21.8%, P1 in 12.6%, P2 in 23.7% and DY in 41.9%. Age- and BMI-adjusted analyses showed that there was an association of parenchymal pattern with overall impression, lobular involution, ductal hyperplasia, sclerosing adenosis, columnar alteration, cyst, duct ectasia and fibrosis. Multivariate analyses found that women of younger age (p<0.001) and with lower BMI (p<0.001), presence of fibrosis (p<0.001) and no involution (p=0.016) were more likely to have P2 or DY parenchymal pattern than women without those characteristics. Conclusion: Among women with benign breast disease, higher MBD is associated with younger age, lower BMI, fibrosis, and lack of lobular involution. These findings, concordant with other studies of MBD, provide insight into underlying mechanisms by which MBD and BBD contribute to breast cancer risk. Citation Format: Karthik Ghosh, Robert A Vierkant, Ryan D Frank, Daniel W Visscher, Vernon S Pankratz, Christopher G Scott, Derek C Radisky, Marlene H Frost, Lynn C Hartmann, Amy C Degnim, Celine M Vachon. Association between mammographic breast density and histologic features of benign breast disease [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 P6-10-14.

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.

Abstract Almost all reported cases of pancreatic ductal adenocarcinoma, the most common form of pancreatic cancer, harbor an oncogenic Kras mutation. Recently, targeting oncogenic Kras to specific cell types in the adult pancreas has shown the acinar compartment to be more susceptible to neoplastic transformation than ductal cells. Acinar to ductal metaplasia (ADM) is a phenomenon where acinar cells undergo a morphological change and begin expressing markers normally found only in ductal cells while losing markers typical of acinar cells. ADM is highly proliferative with the potential to develop into pancreatic intraepithelial neoplasias, a precursor lesion to pancreatic cancer. Acinar cells harvested from mice expressing mutant Kras undergo spontaneous ADM when embedded in 3D collagen cultures, however, we and others have found the epidermal growth factor receptor (EGFR) is required for ADM induced by mutant Kras expression in vitro. Activation of EGFR by treatment of WT collagen embedded acinar cell explants with the EGFR ligand TGF-α has also been shown to induce ADM in a manner requiring Notch pathway activation. Furthermore, it has been demonstrated that expression of Notch2 intracellular domain (N2ICD) is sufficient to induce ADM in WT acinar cells. To directly investigate the relationship of the EGFR, Kras, and Notch signaling pathways in ADM, we examined the effect of Notch signaling in acinar cells harvested from EGFRf/f; Ptf1a+/Cre (EKO) mice, which harbor a pancreas specific deletion of EGFR. Surprisingly, we found that expression of N2ICD failed to induce ADM in acinar cells from EKO mice. We also observed that co-expression of a constitutively active p110α mutant or mutant Kras with N2ICD was able to rescue ADM in acinar cells from EKO mice, though neither was sufficient to drive ADM in the absence of N2ICD. Additionally, treatment of acinar cells from WT mice with either the p110α inhibitor Pik75 or the expression of a dominant negative mutant of the PI3K downstream target Rac1 reduced Erk1/2 phosphorylation, whereas expression of constitutively active p110α increased the level of Erk1/2 phosphorylation. These results demonstrate the importance of EGFR signaling in ADM, and identify the need to determine the mechanism of crosstalk between the PI3K and MAPK pathways in acinar cells. Citation Format: Christopher J. Halbrook, Howard C. Crawford. Notch signaling couples with Kras or PI3K to drive EGFR independent pancreatic acinar to ductal metaplasia. [abstract]. In: Proceedings of the AACR Special Conference on RAS Oncogenes: From Biology to Therapy; Feb 24-27, 2014; Lake Buena Vista, FL. Philadelphia (PA): AACR; Mol Cancer Res 2014;12(12 Suppl):Abstract nr A09. doi: 10.1158/1557-3125.RASONC14-A09