Citations

Background and purpose Many studies demonstrate that both kyphoplasty and vertebroplasty are superior to conservative therapy in the treatment of osteoporotic vertebral body compression fractures. We performed a systematic review and meta-analysis of studies comparing the outcomes of vertebroplasty and kyphoplasty, which included prospective non-randomized, retrospective comparative, and randomized studies. Materials and methods We searched MEDLINE, EMBASE, and the Web of Science databases for studies of kyphoplasty versus vertebroplasty from 1 January 1990 to 30 November 2014 and compared the following outcomes: procedure characteristics, pain and disability improvement, complications and anatomic outcomes. A subgroup analysis was performed comparing pain outcomes based on the risk of bias. Results 29 studies enrolling 2838 patients (1384 kyphoplasty and 1454 vertebroplasty) were included. 16 prospective non-randomized studies, 10 retrospective comparative studies, and 3 randomized controlled studies were included. No significant differences were found in mean pain scores between the two groups postoperatively (2.9±1.5 kyphoplasty vs 2.9±1.7 vertebroplasty, p=0.39) and at 12 months (2.7±1.8 kyphoplasty vs 3.2±1.8 vertebroplasty, p=0.64). No significant differences were found in disability postoperatively (34.7±7.1 kyphoplasty group vs 36.3±7.8 vertebroplasty group, p=0.74) or at 12 months (28.3±16 kyphoplasty group vs 29.6±13.9 vertebroplasty group, p=0.70). Kyphoplasty was associated with lower odds of new fractures (p=0.06), less extraosseous cement leakage (p<0.01), and greater reduction in kyphotic angle (p<0.01). Conclusions No significant difference was found between vertebroplasty and kyphoplasty in short- and long-term pain and disability outcomes. Further studies are needed to better determine if any particular subgroups of patients would benefit more from vertebroplasty or kyphoplasty in the treatment of vertebral body compression fractures.

Abstract Background: Further stratification of the 70-gene MammaPrintTM signature into ‘high’ and ‘ultra-high’ risk groups may help predict chemo-sensitivity. In I-SPY 2, patients were classified as MammaPrint High1 (MP1) or MammaPrint (ultra) High2 (MP2), with MP2 defined as MP_score &lt;-0.154. MP1/MP2 classification was added to HR and HER2 to define the cancer subtypes used in the I-SPY 2 adaptive randomization engine. Neratinib (N), one of the experimental agents evaluated in I-SPY 2, graduated in the HR-HER2+ signature. All patients received at least standard chemotherapy (paclitaxel followed by doxorubicin/cyclophosphamide; T-&gt;AC). HER2- patients were randomized to receive N+T- &gt;AC vs. T-&gt;AC. For HER2+ patients, neratinib was administered in place of trastuzumab (N+T-&gt;AC vs. H+T-&gt;AC). Here, we assess the performance of MP1/MP2 class as a specific biomarker of neratinib response. Methods: 115 patients in the neratinib arm and 76 concurrently randomized controls had Agilent 44K microarrays and pCR data available for analysis. We assess association between MP1/MP2 and response in the neratinib and control arms alone using Fisher’s exact test, and relative performance between arms (biomarker x treatment interaction, likelihood ratio p &lt; 0.05) using a logistic model. This analysis is also performed adjusting for HR status as a covariate, and in receptor subsets. Our study is exploratory with no claims for generalizability of the data. Statistical calculations are descriptive (e.g. p-values are measures of distance with no inferential content). Our analyses do not adjust for multiplicities of other biomarkers in the trial but outside this study. Results: There are 133 MP1 patients (neratinib: 74, Control: 59) and 58 MP2 patients (neratinib: 41, Control: 17), 84% (49) of which are Her2-. The distribution of pCR rates among MP1/MP2 dichotomized groups are summarized in Table 1. Neratinib (n=115)Control (n=76)MP1 (n=74)MP2 (n=41)MP1 (n=59)MP2 (n=17)HER2- (n=105)0 / 1715 / 337 / 395 / 16HER2+ (n=86)22 / 574 / 85 / 200 / 1 MP2, one of the 10 eligible signatures, did not meet the graduation threshold; and MP1/MP2 did not show a significant biomarker x treatment interaction (OR in neratinib relative to control arm = 1.25). The MP1/MP2 x treatment interaction remains non-significant after adjustment for HR and HER2 status (p=0.54). In HER2- patients receiving neratinib, 45% (15/33) of MP2 patients achieved a pCR, compared to 0% (0/17) of MP1 patients. In the HER2- controls, there is a 31% pCR rate in MP2 (5/16) vs. 18% in MP1 (7/39) patients (OR=2.14). This difference in performance between treatment arms appears significant (p=0.041). 90% of HER2+ patients are MP1, thus MP1/MP2 status x treatment interaction within the HER2+ subtype cannot be evaluated. Conclusion: Within the I-SPY 2 population as a whole, MP1/MP2 stratification does not appear to be a specific biomarker of response to neratinib relative to the control arm. The number of HER2- patients is small and precludes any definitive conclusion, but these data motivate further investigation of the biological mechanisms distinguishing MP1 from MP2 to better understand chemotherapy and/or neratanib responsiveness. Citation Format: Christina Yau, Denise M Wolf, Ashish Sanil, Jo Chien, Anne Wallace, Judy Boughey, Doug Yee, Debu Tripathy, Angela DeMichele, Rita Nanda, Steven Chiu, Claudine Isaacs, Kathy Albain, Hank Kaplan, Stacey Moulder, Rebecca Viscusi, Donald Northfelt, Kirsten Edmiston, Anthony Elias, Toncred Styblo, Barbara Haley, Lamorna Brown-Swigart, Susan Flynn, Gillian L Hirst, Meredith Buxton, Nola Hylton, Melissa Paoloni, W Fraser Symmans, Laura Esserman, Don Berry, Minetta C Liu, John W Park, Laura van 't Veer. MammaPrint High1/High2 risk class as a biomarker of response to neratinib plus standard neoadjuvant therapy for breast cancer in the I-SPY 2 TRIAL [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 P3-06-29.

Abstract Background: Further stratification of the 70-gene MammaPrintTM signature into ‘high’ and ‘ultra-high’ risk groups may help predict chemo-sensitivity. In I-SPY 2, patients were classified as MammaPrint High1 (MP1) or MammaPrint (ultra) High2 (MP2), with MP2 defined as MP_score &lt;-0.154. MP1/MP2 classification was added to HR and Her2 to define the cancer subtypes used in the I-SPY 2 adaptive randomization engine. HER2- patients were randomized to receive standard chemotherapy or the oral PARP inhibitor veliparib in combination with carboplatin (V/C) and chemotherapy. V/C graduated in the triple-negative (TN) signature, where MP2 was not an eligible signature for graduation. Here, we assess the performance of MP1/MP2 class as a specific biomarker of response to V/C. Methods:115 HER2- patients (V/C: 71 and concurrent controls: 44) were considered in this analysis. We assess association between MP1/MP2 and response in the V/C and control arms alone using Fisher’s exact test, and relative performance between arms (biomarker x treatment interaction, likelihood ratio p &lt; 0.05) using a logistic model. This analysis is also performed adjusting for HR status as a covariate. To assess MP1/MP2 in the context of the graduating signature, we added the MP2 patients to the graduating TN subset and evaluated the treatment effect in this ‘biomarker-positive’ group. Our study is exploratory with no claims for generalizability of the data. Statistical calculations are descriptive (e.g. p-values are measures of distance with no inferential content). This analysis does not adjust for multiplicities of other biomarkers in the trial but outside this study. Results: In the V/C arm vs. concurrent controls, there were 66 MP1 (V/C: 32, Control: 34) and 49 MP2 patients (V/C: 39, Control: 10), 78% of which are TN. The distribution of pCR rates among MP1/MP2 dichotomized groups are summarized in Table 1. V/C (n=71)Control (n=44)MP1 (n=32)MP2 (n=39)MP1 (n=34)MP2 (n=10)TN (n=59)3 / 819 / 303 / 132 / 8HR+HER2- (n=56)1 / 244 / 94 / 210 / 2 The OR between MP1/MP2 risk groups for predicting pCR is 9.71 in the V/C arm (p=6.63E-05), in comparison to an OR of 0.97 in the control arm (p=1). There is a significant biomarker x treatment interaction (p=0.023), which remains upon adjusting for HR status (p= 0.028). Based on the I-SPY 2 Bayesian model, a Phase III trial with 300 MP2 patients has a 95% predictive probability of success. When the MP2 patients are added to the graduating TN subset, the OR associated with V/C is 4.36, which is comparable to that of the TN signature (OR: 4.29), while increasing the prevalence of biomarker-positive patients by ∼10%. Conclusion: In our exploratory analysis, MP2 suggests higher sensitivity to V/C combination therapy relative to controls. This observation has prompted an investigation into the biological mechanisms distinguishing the MP1/MP2 subtype that may account for this specificity. Citation Format: Denise M Wolf, Christina Yau, Ashish Sanil, Jo Chien, Anne Wallace, Angela DeMichele, Hank Kaplan, Doug Yee, Claudine Isaacs, Kathy Albain, Rebecca Viscuzi, Judy Boughey, Stacey Moulder, Steven Chui, Qamar Khan, Toncred Styblo, Kirsten Edmiston, Donald Northfelt, Anthony Elias, Barbara Haley, Debu Tripathy, Lamorna Brown-Swigart, Susan Flynn, Gillian Hirst, Meredith Buxton, Nola Hylton, Melissa Paoloni, Fraser Symmans, Laura Esserman, Don Berry, Hope Rugo, Olufunmilayo I. Olopade, Laura van 't Veer. MammaPrint High1/High2 risk class as a biomarker of response to veliparib/carboplatin plus standard neoadjuvant therapy for breast cancer in the I-SPY 2 TRIAL [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 P3-06-25.

Abstract Background: There is an increasing recognition that many young women with breast cancer will have favorable outcomes without chemotherapy. We sought to characterize decision-making surrounding adjuvant chemotherapy treatment (CT) in this population for whom chemotherapy has historically been a standard of care. Methods: As part of an ongoing, multi-center, prospective cohort of young women diagnosed with breast cancer at age 40 and younger, we identified 657 women with Stage I-III breast cancer. Participants were asked to complete surveys by mail that included questions about socio-demographics, decision-making, and treatment history within the first year following diagnosis. Tumor characteristics were ascertained via pathology and medical record review. We used Chi-square tests to compare: decisional involvement (patient-driven vs. shared vs. physician-driven), degree of confidence, and feeling informed about the CT decision (the latter two measured on a 0-10 scale, categorized as follows: 0-5=low; moderate=6-8; 9-10=high) between women who did and did not receive CT. To explore clinical appropriateness of the CT decision, we used logistic regression to assess the relationship between tumor characteristics and non-receipt of CT among women with Stage I/II disease. Results: Among women with Stage I (n=250), II (n=312), and III (n=95), disease, 66%, 95%, and 100%, received CT, respectively. A greater proportion of women who had CT were highly confident with their decision compared with women who did not have CT (80% vs. 60%, p&lt;0.0001); women who did not have CT were more likely to report a low level of feeling informed about the CT decision compared to women who received CT (20% vs. 5%, p&lt;0.0001). Women who did not have CT were also more likely to report the final CT decision as made by their doctor (49% vs. 28%) and less likely to report a shared decision (33% vs. 59%, p&lt;0.0001). Non-receipt of CT in women with Stage I/II disease (n=546) was associated within having node negative disease, T1 (vs. T2 or larger), Her2- negative, and hormone receptor positive tumors. Conclusion: Although non-receipt of CT would be expected to be viewed favorably by patients and doctors, we found that women who received CT felt more confident and better informed than those who received no CT. Given that women who did not have CT were also less likely to perceive the CT decision as shared, improved communication together with better decisional support may be beneficial, especially for women who do not receive adjuvant chemotherapy. Citation Format: Shoshana M Rosenberg, Karen Sepucha, Kathryn J Ruddy, Lidia Schapira, Steven Come, Virginia Borges, Evan Morgan, Nancy U Lin, Shari Gelber, Rulla M Tamimi, Ann H Partridge. Decision-making surrounding adjuvant chemotherapy in young women with early stage 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 P2-10-03.

Abstract Background: The development of distant metastases is the strongest prognostic factor associated with cancer mortality. Customization of treatment based on molecular profiling of a patient’s primary tumor has yielded promising results and has opened a new paradigm for treating patients with advanced disease. Nevertheless profiling the primary tumor may not reflect the actionable molecular drivers of the metastatic lesions. In the last few years a large number of genomic and proteomic studies have demonstrated that at the molecular level metastatic lesions significantly differ from matched primary tumors. The impact of metastasis site organ microenvironments on breast cancer primary tumors has been only partially explored. Since most targeted therapies work by modulating aberrantly-activated protein kinase signaling, the aim of this study was to utilize reverse phase protein arrays (RPPA) to explore whether metastatic lesions derived from different patients, but invading the same host target organ showed similarities in their signaling architecture and presented with organ-specific targetable signatures. Methods: Snap frozen material collected from 14 metastatic breast cancer patients enrolled in a prospective phase II trial ("Side Out II") were used for this analysis. Sites of metastasis were: liver (n=7), skin/chest wall (n=4), and lung (n=3). All samples were subjected to Laser Capture Microdissection (LCM) and RPPA to measure the activation/phosphorylation levels of 12 FDA approved drug targets and linked substrates. Results: Among the 7 patients with liver metastases, p70S6K, c-Abl, ERK 1/2 were highly phosphorylated in 5 cases (71.4%), ErbB2/HER2 in 4 cases (57.1%), and AKT in 3 cases (42.8%). On the contrary, of the 4 patients with skin/chest wall lesions 3 showed high activation of ErbB2/HER2, ErbB3/HER3, and ERK 1/2 (75.0%) and 2 of EGFR (50.0%). Of note, none of the skin/chest wall lesions showed activation of AKT and only 1 case presented with activated p70S6K (25.0%). Lung metastasis showed an overall low activation of all 12 analytes measured. Discussion: Although this data is based on a relatively small number of samples and needs further validation, our initial analysis revealed potentially important trends that could have an impact in the prioritization and selection of targeted agents for metastatic breast cancer trials. We found that the distribution of the 12 FDA approved drug targets and downstream substrates varies between different metastatic sites. Thus, the emergent hypothesis from this work is that breast cancer patients with liver metastases may be more susceptible to AKT-mTOR directed targeted therapeutics and patients with skin/chest wall metastasis may benefit from therapies that target EGFR and/or downstream ERK signaling. Citation Format: Mariaelena Pierobon, Stephen P Anthony, K Alex Reeder, Nicholas J Robert, Donald W Northfelt, Mohammad Jahanzeb, Linda Vocila, Julia D Wulfkuhle, Bryant Dunetz, Lance A Liotta, Emanuel F Petricoin. Pathway activation mapping of metastatic breast cancer identifies potential organ-specific signatures: Implications for patient stratification to targeted treatment [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 P1-07-23.

Abstract Oncogenic K-RAS activation is a major menace that drives aggressive tumor progression and metastasis in 30% of all human cancer. Currently, there are no effective therapies to treat stage III and IV metastatic human cancers with oncogenic K-RAS hyperactivation that often confer drug resistance, aggressive tumor growth, systemic metastasis, and poor clinical outcome. Therefore, finding novel approaches and new drug targets to inhibit oncogenic K-RAS pathway activation is an urgent goal and the major challenge in cancer therapy and anti-K-RAS-based drug development. Instead of targeting an upstream signaling module such as EGFR/HER2/K-RAS/B-RAF, we targeted the most downstream signaling module in the oncogenic K-RAS signaling pathway called the SIAH-dependent proteolytic machinery. SIAHs are the human homologs of Seven-In-Absentia (SINA), an evolutionarily conserved RING E3 ligase - the most downstream signaling module and a critical “gatekeeper” required for proper RAS signal transduction. Guided by the insights and fundamental principles learned from the Drosophila RAS signal transduction, we conducted preclinical studies to dissect SIAH function in promoting the oncogenic K-RAS-driven tumorigenesis and metastasis in human cancer. We found that (1) SIAH is a new biomarker reflective of oncogenic K-RAS activation in human cancer, and (2) SIAH loss-of-function is highly effective to block tumorigenesis and metastasis against the well-established, end-stage and metastatic pancreatic cancer and triple negative breast cancer (TNBC). These findings demonstrate that SIAH is an attractive and logical new therapeutic target for developing novel and effective anti-K-RAS and anticancer therapy against metastatic human cancer. Through our work, SIAH has emerged as a promising new drug target against oncogenic K-RAS hyperactivation in metastatic human cancer cells. Using anti-SIAH molecules to block oncogenic K-RAS signaling in human cancer is an excellent example of science going “from the bench (basic research in fruit flies) to the bedside (preclinical studies and ultimately clinical trials)”. As a highly evolutionarily conserved E3 ligase that is the most downstream and the most conserved “signaling gatekeeper” in the oncogenic K-RAS signaling network, SIAH is uniquely and strategically positioned to become a great and logical anti-K-RAS drug target. Our preclinical studies have demonstrated that “SIAH-dependent proteolysis” is indeed an Achilles' heel in metastatic human cancer cells. Knowledge gained from our preclinical study has promising translational values. Anti-SIAH-based small molecule inhibitors are likely to aid in expanding our limited arsenal of novel anti-K-RAS-based anticancer therapies. By attacking the oncogenic K-RAS pathway using multi-pronged synergistic inhibitions at upstream (EGFR/HER2 membrane receptors), midstream (K-RAS/B-RAF/MEK/mTOR) and downstream (SIAH E3 ligase) signaling modules in parallel, we will be in a position to control the late-stage, relapsed and metastatic human cancers by shutting down the hyperactivated K-RAS signaling transduction cascades in cancer cells in the future. Citation Format: Minglei Bian, Yang Liao, Vasilena Zheleva, Zena Urban, Monicah Njogu, Justin J. Odanga, Andrew J. Isbell, Roger R. Perry, Richard A. Hoefer, Thomas C. Smyrk, Gloria M. Petersen, Amy H. Tang. Attacking the most downstream “gatekeeper,” the SIAH-dependent proteolytic machinery, in the oncogenic ERBB/K-RAS signaling pathway to block tumorigenesis and control metastasis in human cancer. [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 A26. doi: 10.1158/1557-3125.RASONC14-A26

Abstract To identify genetic variants that contribute to colorectal cancer (CRC) susceptibility, we performed a meta-analysis of two genome-wide association studies in 2,627 cases and 3,797 controls of Japanese ancestry and 1,894 cases and 4,703 controls of African ancestry, followed by a replication of genome-wide statistically significant associations (P &lt; 5E-8) in 16,823 cases and 18,211 controls of European ancestry. This study revealed a new pan-ethnic CRC risk locus at 10q25 (rs12241008, intronic to VTI1A; P=1.5E-9), providing additional insight into the etiology of CRC and highlighting the value of association mapping in diverse populations. Citation Format: Hansong Wang, Terrilea Burnett, Suminori Kono, Christopher Haiman, Motoki Iwasaki, Lynne Wilkens, Lenora Loo, David Van Den Berg, Laurence Kolonel, Brian Henderson, Temitope Keku, Robert Sandler, Lisa Signorello, William Blot, Polly Newcomb, Mala Pande, Christopher Amos, Dee West, Stéphane Bézieau, Sonja Berndt, Brent Zanke, Li Hsu, Noralane Lindor, Robert Haile, John Hopper, Mark Jenkins, Steven Gallinger, Graham Casey, Stephanie Stenzel, Fredrick Schumacher, Ulrike Peters, Stephen Gruber, Shoichiro Tsugane, Dan Stram, Loic Le Marchand. Transethnic genome-wide association study of colorectal cancer identifies a new susceptibility locus in VTI1A. [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 LB-282. doi:10.1158/1538-7445.AM2014-LB-282

Abstract Background: Overexpression of COX-2 has been associated with worse outcome in NSCLC. In C30203, we found that administration of the selective COX-2 inhibitor celecoxib in addition to chemotherapy in advanced NSCLC improved outcome (progression free and overall survival, PFS, OS) in pts with moderate to high COX-2 expression by immunohistochemistry (IHC). C30801 was designed to prospectively confirm that finding. Patients and Methods: Pts with NSCLC (stage IIIb with pleural effusion, IV 6th ed) were pre-registered and biopsy specimens analyzed for COX-2 by IHC. Pts with COX-2 expression &gt; or = 2, PS 0-2 and normal organ function were eligible. Chemotherapy was determined by histology: carboplatin (AUC = 6), pemetrexed (500 mg/m2) d 1, q21 days for pts with non-squamous NSCLC; carboplatin(AUC=5.5) d1, gemcitabine (1000 mg/m2) d 1,8 for pts with squamous histology. Randomization was to celecoxib (400 mg bid) (Arm A) or placebo (Arm B). The primary endpoint was to demonstrate improvement in PFS in patients with COX-2 index &gt;=4 with hazard ratio of 0.645. Results: The study was halted by the DSMB for futility after 312 of the planned 322 pts were randomized. The current analysis is based upon the first 300 pts. There were no significant differences between the groups (Table). There was a possible harmful effect for COX-2 inhibition in the COX-2 2-3 subset (OS HR = 1.75, p =.0977). Toxicity was similar for both arms. Subset analyses evaluating histology, chemotherapy regimen, incremental COX-2 expression did not demonstrate any advantage for COX-2 inhibition. Conclusions: 1. COX-2 expression by IHC failed to select pts who could benefit from selective COX-2 inhibition. 2. COX-2 inhibition did not significantly increase toxicity associated with chemotherapy or increase cardiovascular morbidity. 3. We will evaluate other possible determinants of toxicity and response to COX-2 inhibition. OutcomeArm AArm BCOX-2 2-3 (n=37)COX-2 &gt; or = 4 (n=111)COX-2 2-3 (n=46)COX-2 &gt; or = 4 (n=106)PFS (months)4.404.934.606.11OS (months)9.0310.5814.8512.68 Citation Format: Martin J. Edelman, Xiaofei Wang, Lydia Hodgson, Richard T. Cheney, Maria Baggstrom, Thomas Sachdev, Ajeet Gajra, Erin Bertino, Karen Reckamp, Julian Molina, Joan Schiller, Kisha Mitchell-Richards, Paula Friedman, Jon Ritter, Everett Vokes, Alliance for Clinical Trials in Oncology. Phase III randomized, placebo controlled trial of COX-2 inhibition in addition to standard chemotherapy for advanced non-small cell lung cancer (NSCLC):CALGB 30801 (Alliance). [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 CT238. doi:10.1158/1538-7445.AM2014-CT238

Abstract Hyperactivation of the oncogenic K-RAS pathway leads to increased cell proliferation, tumor growth, and oxidative stress associated with increased ROS production, heightened mitochondrial bioenergetics, and altered cancer metabolisms. Downstream of the K-RAS pathway, Seven-In-Absentia human Homolog (SIAH) is required for proper ERBB/RAS signal transduction. Human peroxiredoxin (PRDX) is an antioxidant protein, whose precise role in modulating oxidative stress during oncogenesis remains to be elucidated. Increased levels of oxidative stress alter the bioenergetics and functional integrity of mitochondrial biology under cellular stress. This study aims to elucidate the biological interaction previously detected between PRDX and SIAH2 via biochemical assays. We plan to investigate the functional role of SIAH2-PRDX interaction in modulating the stress response and adaptive cell survival in K-RAS-driven tumors. Also, we would like to investigate the biological significance of SIAH2-PRDX interaction in response to increased cellular stress in K-RAS-driven human cancer cells treated with standard chemotherapies. Mitochondrial tracking (MITO-tracker®) was used to evaluate mitochondrial integrity of SIAH-proficient and SIAH-deficient human lung (A549) and cervical (HeLa) cancer cells over six days. Immunofluorescence staining and bright field imaging were performed using DOX-inducible human breast (MDA-MB231) and cervical (HeLa) cancer cells to compare changes in organelle integrity and mitochondrial morphology, altered expression of the oxidative stress biomarker and cell death biomarkers in response to induction of the SIAH- proficient and SIAH-deficient states in highly aggressive human cancer cells. By using human pancreatic cancer tissue microarrays (TMAs), we found that the antioxidant protein PRDX is significantly upregulated and co-expressed with SIAH in human pancreatic tumor biospecimens. It seems that PRDX is an indicative biomarker of cellular and oncogenic K-RAS-induced oxidative stress in human pancreatic cancer. By blocking SIAH2 function downstream of the K-RAS signaling pathway, oxidative stress levels were markedly increased, evidenced by mitochondrial aggregations and dysfunction in both human lung and cervical cancer cells. In response to anti-SIAH2 therapy, human TNBC, NSCLC and cervical cancer cells underwent dramatic morphological changes due to the significant loss of cell junction, focal adhesion and cell attachment. These data have shown that anti-SIAH2-based anti-K-RAS and anticancer therapy is highly effective in inducing massive cell death in several highly invasive and metastatic cancer lines. Further investigation into the molecular mechanisms of anti-SIAH2-induced cellular stress and cell death may contribute to the future drug development and validation of a new and effective anti-SIAH2-based targeted therapy against metastatic human cancer in the future. Citation Format: Zena M. Urban, Lauren van Reesema, Minglei Bian, Thomas C. Smyrk, Gloria Peterson, Amy H. Tang. Inhibition of SIAH E3 ligase function leads to increased cell death in metastatic human cancer cells. [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 4442. doi:10.1158/1538-7445.AM2014-4442