Citations

Abstract Purpose: Immunotherapeutic strategies to treat patients with renal cell carcinoma (RCC) offer new opportunities for disease management. Further improvements to immunotherapy will require additional understanding of the host response to RCC development. Experimental Design: Using a novel approach to understanding the immune status of cancer patients, we previously showed that patients with a certain immune profile had decreased overall survival. Here, we examine in more detail the phenotypic changes in peripheral blood and the potential consequences of these changes in RCC patients. Results: We found that CD14+HLA-DRlo/neg monocytes were the most predominant phenotypic change in peripheral blood of RCC patients, elevated nearly 5-fold above the average levels measured in healthy volunteers. Intratumoral and peritumoral presence of CD14 cells was an independent prognostic factor for decreased survival in a cohort of 375 RCC patients. The amount of peripheral blood CD14+HLA-DRlo/neg monocytes was found to correlate with the intensity of CD14 staining in tumors, suggesting that the measurement of these cells in blood may be a suitable surrogate for monitoring patient prognosis. The interaction of monocytes and tumor cells triggers changes in both cell types with a loss of HLA-DR expression in monocytes, increases of monocyte survival factors such as GM-CSF in tumors, and increased production of angiogenic factors, including FGF2. Conclusions: Our results suggest a model of mutually beneficial interactions between tumor cells and monocytes that adversely affect patient outcome. Clin Cancer Res; 21(18); 4224–33. ©2015 AACR.

Positioning‐related injuries caused during surgery under anesthesia are most likely multifactorial. Pathologic mechanical forces alone (overstretching and/or ischemia from direct compression) may not fully explain postsurgical neuropathy with recent evidence implicating patient‐specific factors or perioperative inflammatory responses spatially and even temporally divorced from the anatomical region of injury. The aim of this introductory article is to provide an overview of anatomic considerations of these mechanical forces on soft and nervous tissues along with factors that may compound compression or stretch injury. Three subsequent articles will address specific positioning‐related anatomic considerations of the (1) upper extremities, (2) lower extremities, and (3) central nervous system and soft tissues. Clin. Anat. 28:678–682, 2015. © 2015 Wiley Periodicals, Inc.

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 <-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->AC). HER2- patients were randomized to receive N+T- >AC vs. T->AC. For HER2+ patients, neratinib was administered in place of trastuzumab (N+T->AC vs. H+T->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 < 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 <-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 < 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: In the adjuvant setting, HER2 breast cancer patients treated with trastuzumab along with chemotherapy have superior survival compared to patients treated with chemotherapy alone (Perez EA, et al. J Clin Oncol. 2013 31:2115-22). Functional evidence suggests a role for the FC gamma receptor genes in antibody response. Mice deficient in the FC gamma receptor genes show significantly reduced antitumor effect. Polymorphisms within FCGR2A and FCGR3A are associated with binding affinity of natural killer cells to the IgG1 portion of trastuzumab and a polymorphism in FCGR2B (I232T, T allele) is associated with impaired negative regulatory activity. Association of FC gamma receptor polymorphisms with clinical response among trastuzumab-treated patients is equivocal with both positive (Musolino A, et al. J Clin Oncol. 2008 26:1789-96) and negative associations (Hurvitz SA, et al. Clin Cancer Res. 2012 18:3478-86), a lack of sufficiently powered clinical samples and a lack of cohorts with clearly demonstrated survival benefit to trastuzumab containing regimens. Methods: Genomic DNA was analyzed for FcyRIIIa, FcyRIIa, and FcyRIIb polymorphisms (FCGR3A V158F, FCGR2A H131R and FCGR2B I232T) using Taqman SNP real-time PCR assays (Applied Biosystems) in 1,336 patients from the N9831 clinical trial of adjuvant trastuzumab in HER2+ breast cancer. 1325 patients were evaluable. Patients in Arm A (N=419) received chemotherapy only. Patients in Arms B (N=469) and C (N= 437) were treated with chemotherapy and trastuzumab (sequentially in Arm B and concurrently in Arm C). We performed Kaplan-Meier analyses of disease free survival (DFS) by arm and genotype for each polymorphism. Results: There were only minor differences in demographics and tumor features when comparing the subset with DNA to other N9831 participants who did not provide DNA. Patients who provided DNA in Arms B and C demonstrated superior DFS relative to patients in Arm A who provided DNA (p<0.001). Genotype distributions in the N9831 population for FCGR2A and FCGR3A polymorphisms were in Hardy-Weinberg equilibrium, p>0.05 and FCGR2B, p>0.01. In contrast to previous reports in the metastatic setting, we did not find that trastuzumab-treated patients who had the FCGR3A 158 V and/or FCGR2A 131 H genotypes demonstrated superior DFS to those without those genotypes. Similarly, we did not see an effect of FCGR2B I232T with the exception that I/I patients (p<0.001) apparently derived more benefit, in terms of DFS, from trastuzumab than did T carriers (p=0.81). However, 5-year DFS was not different between these two groups, I/I and T carriers within Arms B/C. Conclusions: Our analysis failed to reveal strong associations between FCGR genotypes and outcome in patients with HER2+ breast cancer treated with trastuzumab. While the present data do not preclude a functional role for FC gamma receptors in the clinical activity of trastuzumab, the results suggest that these naturally occurring polymorphisms may have minor (if any) impact in the adjuvant setting, which is consistent with previous findings by Hurvitz and colleagues. Citation Format: Mark Pegram, Rebecca M. Olson, Nadine Norton, Kathleen Tenner, Karla L. Ballman, Raphael Clynes, Keith L. Knutson, Edith A. Perez. Analysis of the associations of FC gamma receptor polymorphisms (FCGR3A, FCGR2A, and FCGR2B) with outcome in HER2+ breast cancer patients treated with trastuzumab in NCCTG (Alliance) trial N9831. [abstract]. In: Proceedings of the AACR Special Conference on Advances in Breast Cancer Research: Genetics, Biology, and Clinical Applications; Oct 3-6, 2013; San Diego, CA. Philadelphia (PA): AACR; Mol Cancer Res 2013;11(10 Suppl):Abstract nr B123.

Abstract Background: Diffuse large B-cell lymphoma (DLBCL) is the most common lymphoma subtype and is clinically aggressive. Relatives of DLBCL patients are at elevated risk for DLBCL. In small genome-wide association studies (GWAS) in which all NHL subtypes were combined, no conclusive loci for DLBCL have been previously identified in individuals of European background, whereas a recent study conducted in East Asia identified a locus at 3q27. Methods: To identify genetic susceptibility loci for DLBCL, we conducted a meta-analysis of three new GWAS and one prior scan, totaling 3,857 DLBCL cases and 7,666 controls of European ancestry. Imputation was used to combine all the data using the 1000 Genomes Project release v3 and IMPUTE2. Based on these findings, we selected 6 promising SNPs for genotyping in an additional 202 cases and 3,431 controls, which were then included in a second meta-analysis. SNPTEST was used to estimate odds ratios (ORs), using the additive model and adjusting for age, gender and significant eigenvectors. Results: In our multi-stage analysis, five independent SNPs in four loci achieved genome-wide significance marked by rs116446171 at 6p25.3 (EXOC2; OR=2.33, P=1.60x10-20), rs13255292 and rs4733601 at 8q24.21 (PVT1; OR=1.23, P=4.86x10-12 and OR=1.18, P=1.63x10-8, respectively), rs2523607 at 6p21.33 (HLA-B; OR=1.34, 3.35x10-9) and rs2681416 at 3q13.33 (CD86; OR=1.20, P=6.04x10-9). The two 8q24.21 SNPs displayed minimal linkage disequilibrium (r2=0.03) and conditional analysis supported their independence. We did not observe a notable signal for a locus previously reported for DLBCL on 3q27 in East Asia, rs6773854 (OR=1.06, P=0.81). We estimated that common SNPs, including but not limited to the loci discovered in this study, explain approximately 16% of the variance for DLBCL risk overall. Discussion: The susceptibility locus at 6p25.3 maps near a plausible DLBCL candidate gene, EXOC2 (exocyst complex component 2), which interacts with Ral proteins, and disruption of the Ral-exocyst regulatory node impacts cellular and developmental processes associated with malignant transformation and progression. The two 8q24.21 variants are approximately 1Mb telomeric to the 8q24 region linked with multiple cancers including CLL. Both variants are positioned in close proximity to PVT1, which is a non-coding RNA implicated in the MYC activation, and MYC is known to be deregulated in some DLBCLs. The locus at 3q13.33 maps to CD86 (B7-2), a B-7 family member that along with CD80 (B7-1) is essential in cognate interactions between T- and B-lymphocytes; both play key roles in immunodeficiency, autoimmune diseases, and in anti-tumor immunity. Finally, we had multiple signals in the HLA region, the strongest of which was at 6p21.33 near HLA-B. HLA-B encodes the HLA class I heavy chain paralogue, which heterodimerizes with a light chain (β2 microglobulin) and plays a central role in presenting intracellularly processed self or foreign antigens to CD8+ cytotoxic T lymphocytes. Class I molecules have been extensively linked to the risk of a variety of immune-mediated diseases and cancers including DLBCL. Conclusions: These data provide substantial new evidence for genetic susceptibility to this B-cell malignancy, and point towards pathways involved in immune recognition and immune function in the pathogenesis of DLBCL. Citation Format: James R. Cerhan, Sonja I. Berndt, Joseph Vijai, Hervé Ghesquières, James McKay, Sophia S. Wang, Zhaoming Wang, Meredith Yeager, Alexandra Nieters, David Cox, Alain Monnereau, Christopher Flowers, Anneclaire J. De Roos, Angela R. Brooks-Wilson, Qing Lan, Gianluca Severi, Mads Melbye, Rebecca D. Jackson, Lauren R. Teras, Mark Purdue, Claire Vajdic, Demetrius Albanes, Kimberly A. Bertrand, Anne Zeleniuch-Jacquotte, Simon Crouch, Yawei Zhang, Paolo Vineis, Susan L. Slager, Karin E. Smedby, Gilles Salles, Christine F. Skibola, Nathaniel Rothman, Stephen J. Chanock, on behalf of the NHL GWAS Project. Genome-wide association study identifies multiple susceptibility loci for diffuse large B-cell lymphoma. [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-272. doi:10.1158/1538-7445.AM2014-LB-272

Abstract Marginal zone lymphomas (MZL) are a group of indolent non-Hodgkin's B-cell lymphomas (NHL) comprising extranodal MZL of mucosa-associated lymphoid tissue (MALT) type, splenic MZL and nodal MZL. MZL comprises 7-12% of adult NHLs. The genetic etiology of MZL is poorly understood. To better understand the genetic risk factors for MZL, we conducted the first genome-wide association study (GWAS) of this lymphoid malignancy. The GWAS included 824 MZL cases and 6,220 controls of European ancestry from 22 studies of NHL. Genotyping was carried out at the Cancer Genomics Research Laboratory (CGR) of NCI using Illumina Human OmniExpress arrays. Standard genotyping quality controls were performed. Imputation of common SNPs was performed using IMPUTE2 software and 1000 Genomes Project release version 3 data. Association testing was subsequently performed using SNPTEST, assuming a log-additive genetic model adjusting for age, gender and three significant eigenvectors. We identified one locus at 6p21.32 within the HLA class II region that attained genome-wide significance (P<5x10-8). When a small number of additional cases (n=58) and controls (n=66) genotyped using Taqman assays were included, rs9461741 (BTNL2) was associated with an increased risk of MZL (per-allele odds ratio = 2.38, 95% confidence interval: 1.74-3.24; P=4.32x10-8). Other SNPs at the 6p21.32 locus were also highly associated with MZL, suggesting that this is unlikely to be a chance finding. Promising signals yet to be confirmed were also observed on chromosomes 3 and 14. The BTNL2 protein has extracellular immunoglobulin domains and is expressed in multiple tissues including various immune organs and the gut and it inhibits T-cell activation. Genetic variability at BTNL2 has been associated with inflammatory and infectious phenotypes, highlighting the importance of this locus for immune diseases. In conclusion, findings from this GWAS identify the HLA class II region as an important susceptibility locus for MZL. Citation Format: Joseph Vijai, Zhaoming Wang, Sonja I. Berndt, Susan L. Slager, James R. Cerhan, Christine Skibola, Sophia S. Wang, Angela R. Brooks-Wilson, Silvia de Sanjose, Paige M. Bracci, Mads Melbye, Bengt Glimelius, Rebecca D. Jackson, Wendy Cozen, Nikolaus Becker, Lauren R. Teras, John J. Spinelli, Jenny Turner, Qing Lan, Mark P. Purdue, Kimberly A. Bertrand, Kenneth Offit, Paolo Vineis, Brian K. Link, Graham G. Giles, Anne Zelenuich-Jacquotte, Alain Monnereau, Maria Grazia Ennas, Demetrius Albanes, Laurie Burdett, Nathaniel Rothman, Stephen J. Chanock, Alexandra Nieters, On behalf of the NHL GWAS Consortium. A genome-wide association study suggests evidence of variants at 6p21.32 associated with marginal zone lymphoma. [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 5071. doi:10.1158/1538-7445.AM2014-5071

Abstract Interferon regulatory factor-4 (IRF4) is a tightly-regulated transcription factor involved in growth and differentiation of normal lymphocytes. IRF4 is expressed in multiple lymphoid malignancies and its expression drives tumor growth. Thus, characterization of the molecular events regulating IRF4 levels is key to design any targeting strategy. Here, we define a novel regulatory mechanism controlling IRF4 expression in peripheral T-cell lymphoma (PTCL), an aggressive non-Hodgkin lymphoma with poor overall survival rates and high levels of this transcription factor. In normal T cells, IRF4 was induced upon external activation of protein kinase C (PKC) by phorbol myristate acetate and ionomycin, an effect reversed by the PKC inhibitor, enzastaurin. Unlike normal T cells, PTCL cells constitutively expressed IRF4 in the absence of external stimulation, and this expression was resistant to enzastaurin. To identify regulators of IRF4 expression in PTCL, we performed a pharmacological screen using inhibitors that targeted PKC-associated pathways, including mitogen-activated protein kinases, PI3K/AKT/mTOR, and NF-κB. Of the inhibitors tested, only the proteasome inhibitor, bortezomib, showed a decrease in IRF4 expression in a dose- and time-dependent manner. To confirm this result we used a more specific NF-κB inhibitor blocking IκB kinase, BMS-345541. This inhibitor dramatically reduced IRF4 expression by 95.6% (P<0.0001). We used cell-based assays to investigate further the role of NF-κB in the transcriptional regulation of IRF4. A reporter assay for the IRF4 promoter demonstrated reduced promoter activity by siRNA knockdown of RelB and p52 NF-κB subunits to 31.4% and 36.9% of control (P=0.009). IRF4 promoter activity also was inhibited 67.9% by IκBαΔN, a dominant negative inhibitor of NF-κB activity (P=0.002), and was increased 71% by siRNA knockdown of IκBα (P<0.05). Chromatin immunoprecipitation assays confirmed the occupancy of NF-κB subunits in the IRF4 promoter, and this interaction was diminished in the presence of BMS-345541. Finally, knockdown of RelB and p52 subunits had a tendency to decrease IRF4 gene expression by 24.4% and 27.3% (P=0.1). Taken together, these data demonstrate transcriptional regulation of IRF4 by the NF-κB family in PTCL, and suggest the NF-κB pathway may represent a therapeutic target for PTCLs with concurrent IRF4 and NF-κB expression. Citation Format: Rebecca L. Boddicker, N. Sertac Kip, Luciana L. Almada, Julie C. Porcher, Deanna M. Grote, Stephen M. Ansell, Martin E. Fernandez-Zapico, Andrew L. Feldman. Interferon regulatory factor-4 is transcriptionally regulated by NF-κB in peripheral T-cell lymphomas. [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 2323. doi:10.1158/1538-7445.AM2014-2323

Abstract Oncogenic EGFR/HER2/K-RAS activation is known to reduce focal adhesion and cell attachment, alter cell junction, and increase cell motility during normal tissue development as well as tumor invasion and cancer metastasis. Deciphering the mechanisms that promote cancer cell dissemination and metastasis in response to oncogenic ERBB/K-RAS “pathway” activation and finding novel targets for inhibiting invasion and metastasis remains an important goal in cancer biology. SIAH2, the human homologue of a highly conserved RING-domain E3 ubiquitin ligase SINA that is the most downstream signal modulator identified in Drosophila RAS signaling pathway, is critically required for proper mammalian ERBB/K-RAS signal transduction. SIAH2 insufficiency was shown to impede oncogenic K-RAS signal transduction, thereby obstructing K-RAS-driven tumorigenesis and metastasis in the preclinical models. However, the exact molecular mechanism of SIAH2 function downstream of the oncogenic ERBB/K-RAS activation remains to be characterized in human cancer cells. In this study, we use immunoprecipitation to isolate novel SIAH2-interacting proteins from multiple highly aggressive human cancer cells with oncogenic K-RAS hyperactivation. Three LIM-domain focal adhesion proteins (Trip6/FHL2/LPXN) were identified by Mass Spectrometry analysis, and their interactions with SIAH2 were verified biochemically by bi-directional co-immunoprecipitation (co-IP). Trip6/FHL2/LPXN has been reported to play important roles in cell focal adhesion formation and cell migration. We demonstrated that SIAH2 biochemically interacts with, ubiquitinates and thereby causes the degradation of these LIM domain proteins, demonstrating that TRIP6, FHL2 and LPXN are bona fide SIAH2 substrates in vivo. Our immunofluorescence (IF) staining results showed that SIAH2-deficiency disrupts Trip6/FHL2/LPXN localization at the focal adhesion site, results in defects in focal adhesion, cell junction, cell attachment and cell motility. Conversely, ectopic expression of TRIP6, FHL2 and LPXN can partially rescue SIAH2-deficient cancer cells from the pronounced defects in cell motility, cell death and tumor growth. The discovery that SIAH2 directly modulates focal adhesion may provide a novel molecular mechanism to explain the well-documented increases in cancer cell dissemination, tumor invasion and metastasis in response to ERBB/K-RAS pathway activation in human cancer cells. We may have uncovered a novel function of SIAH in modulating focal adhesion and cell junction in human cancer cells. By circumventing EGFR/HER2/K-RAS signaling pathway at its most downstream signaling module, we hope to validate and develop novel anti-SIAH-based anti-K-RAS anticancer therapies against oncogenic K-RAS-driven tumors in the future. Citation Format: Ming Bian, Yang Liao, Rebecca L. Schmidt, Monicah M. Njogu, Rie Takahashi, Zandra E. Walton, Amy H. Tang. Inhibiting SIAH2 E3 ligase function disrupts focal adhesion and cell junction, inhibits cell mobility and attachment, and blocks tumor invasion and metastasis in oncogenic K-Ras-driven tumors. [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 1965. doi:10.1158/1538-7445.AM2014-1965