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BACKGROUND AND STUDY AIMS: Endoscopic mucosal resection (EMR) has been carried out for high-grade dysplasia (HGD) and intramucosal carcinoma (IMCA) in Barrett’s esophagus using two different cap-assisted techniques, the ”inject, suck, and cut“ and the ”band and snare.“ Previous work has demonstrated comparable specimen diameters. However, the two techniques have not been previously compared with respect to depth of resection. PATIENTS AND METHODS: From a database of patients with Barrett’s esophagus, we identified 40 consecutive specimens removed using EMR from patients with HGD or IMCA, 20 each from the ”inject, suck, and cut” and the ”band and snare” techniques. Specimens were evaluated and measured separately by two pathologists for greatest diameter and depth, and for the presence of submucosa and muscularis propria at the deepest margin of resection. Follow-up data were collected regarding clinical outcome and stricture formation. RESULTS: The mean depth of the specimens from the two techniques was not significantly different (0.51 cm vs. 0.50 cm, P = 0.76). All specimens contained substantial submucosa, allowing accurate staging of the neoplastic lesions resected. Muscularis propria was identified at the base of 65 % of the ”band and snare” and 50 % of the ”inject, suck, and cut” specimens ( P = 0.52). CONCLUSIONS: The ”inject, suck, and cut” and ”band and snare” techniques both yield equivalent adequate depth of histological specimens from Barrett’s esophagus with HGD or IMCA, and both provide accurate pathological staging.

B-cell post-transplant lymphoproliferative disorders (PTLD) are classified as early lesions, polymorphic lymphomas (P-PTLD) and monomorphic lymphomas (M-PTLD). These morphologic categories are thought to reflect a biologic continuum, although supporting genetic data are lacking. To gain better insights into PTLD pathogenesis, we characterized the phenotypes, immunoglobulin (Ig) gene alterations and non-Ig gene (BCL6, RhoH/TTF, c-MYC, PAX5, CIITA, BCL7A, PIM1) mutations of 21 PTLD, including an IM-like lesion, 8 P-PTLD and 12 M-PTLD. Gene expression profile analysis was also performed in 12 cases. All PTLD with clonal Ig rearrangements showed evidence of germinal centre (GC) transit based on the analysis of Ig and BCL6 gene mutations, and 74% had a non-GC phenotype (BCL6 +/- MUM1+). Although surface Ig abnormalities were seen in 6/19 (32%) PTLD, only three showed 'crippling' Ig mutations indicating other etiologies for loss of the B-cell receptor. Aberrant somatic hypermutation (ASHM) was almost exclusively observed in M-PTLD (8/12 vs. 1/8 P-PTLD) and all three recurrent cases analysed showed additional mutations in genes targeted by ASHM. Gene expression analysis showed distinct clustering of PTLD compared to B-cell non-Hodgkin lymphomas (B-NHL) without segregation of P-PTLD from non-GC M-PTLD or EBV+ from EBV- PTLD. The gene expression pattern of PTLD appeared more related to that of memory and activated B-cells. Together, our results suggest that PTLD represent a distinct type of B-NHL deriving from an antigen experienced B-cell, whose evolution is associated with accrual of genetic lesions.

564 Background: Ovary mets constitute 5-10% of CRC mets, are associated with poor prognosis, cause morbidity due to disproportionately rapid growth compared with other mets and are less responsive to chemotherapy. The optimal management of ovary mets and the molecular basis of their unique growth pattern is unknown. Methods: 505 MSKCC patients with CRC (ICD-9 153, 154) and ovary mets (ICD-9 198.6) were identified. Patients without available pathology, with appendix cancer or only serosal ovary mets were excluded. Regression models were used to identify predictors of progression-free survival (PFS) and overall survival (OS) after surgery. Targeted exome sequencing of 341 cancer-associated genes was performed on 34 CRC ovary mets, including 20 matched pairs or trios of primary tumors, ovary mets and other mets from the same patient. Results: 184 patients with surgically resected CRC ovary mets were evaluated (median age 50 (17-86); OS 40 months (0.8-218) from CRC diagnosis, 23 months (0.2-199) from oophorectomy). 93/116 (80.2%) evaluable patients had concurrent growth of ovary mets on chemotherapy but shrinkage of other mets. In multivariate analysis, optimal surgical debulking was associated with improved PFS (HR = 0.11 (0.04-0.36)) and OS (HR = 0.42 (0.28-0.63)). Discordant ovary therapy response was associated with early progression (HR = 20.8 (1.59-274), and post-oophorectomy chemotherapy with reduced mortality (HR = 0.53 (0.33-0.84)). Ovary mets had increased KRAS (61.7% vs. 45.2%, p= 0.05) and SMAD4 (29.4% vs. 15.5%, p= 0.04) mutations compared to a 453 CRC cohort without ovary mets. In matched trios, mutations were largely concordant across tumor sites and no recurrent ovary met-specific mutations were found. However, 3/14 cases had identical mutations in the ovary mets and primary tumors, but additional private mutations in other mets. Conclusions: CRC ovary mets have frequent KRAS and SMAD4 mutations. Matched trios show clonal similarities between primary tumors and ovary mets, and divergence from other mets. Complete surgical resection of ovary mets is associated with substantially improved PFS and OS, similar to outcomes for localized CRC.

An increased incidence of acute myeloid leukemia (AML) has recently been documented in patients post-solid organ transplantation but the incidence and types of myelodysplastic syndromes (MDS) occurring in this patient population are not known. We identified 5 patients (3M, 2F, age 48-64 years) who developed MDS ranging from 1.8 to 25 years (median 4.2 years) post-solid organ transplantation, only 2 patients had received azathioprine. The cumulative incidence of MDS in heart and lung transplant recipients at 15 years was 0.5% and 1.8%, respectively, which is markedly higher compared to the general population. Low-risk types of MDS predominated, 3 of 5 patients are alive (median 3.9 years) since diagnosis. Deletions of chromosome 20q, which have not been previously reported in post-transplant MDS/AML, were identified in 3 cases. Our findings expand the morphologic and cytogenetic spectrum of MDS occurring post-solid organ transplantation and suggest that mechanisms beside azathioprine toxicity might be important in disease pathogenesis.

Background: RAF and EGFR inhibitor combinations have shown promising clinical activity in patients with BRAF V600E colorectal cancer, but resistance invariably develops. Methods: To define mechanisms of resistance to RAF/EGFR inhibition, we analyzed pre-treatment and disease progression samples from patients with BRAF mutant colorectal cancer using our custom next-generation sequencing platform, MSK-IMPACT (Integrated Mutation Profiling of Actionable Cancer Targets). Cell line and patient derived xenograft models were generated to investigate the effects of the genetic alterations identified at disease progression. Results: We identified alterations predicted to result in RAF dimerization and re-activation of ERK signaling in seven of eight post-progression tumors. These alterations included an intragenic deletion in BRAF encompassing the RAS binding domain, KRAS and NRAS mutations, and KRAS, NRAS, and BRAF amplifications. Notably, these alterations were rapidly enriched in the presence of drug treatment but selected against in the absence of drug exposure. A novel RAF inhibitor, that equipotently inhibits RAF mutant monomers and dimers, effectively suppressed ERK signaling in the RAF/EGFR resistant colorectal tumors at drug doses that did not inhibit ERK signaling in RAS/RAF wild-type cells. Treatment with this novel RAF inhibitor was able to overcome resistance in cell line and patient derived xenograft models. Conclusions: Our data suggest that alterations that promote RAF dimers, which are resistant to first generation RAF inhibitors, are a unifying mechanism of RAF/EGFR inhibitor resistance in patients with BRAF mutant colorectal cancer. These results support the testing of RAF dimer inhibitors in combination with EGFR inhibitors in patients with BRAF V600E colorectal cancer. Citation Format: Rona Yaeger, Zhan Yao, David M. Hyman, Jaclyn F. Hechtman, Efsevia Vakiani, Andrea Cercek, Jose Baselga, Elisa DeStanchina, Leonard Saltz, Michael F. Berger, David B. Solit, Neal Rosen. RAF kinase dimerization mediates clinical acquired resistance to RAF/EGFR inhibition in BRAF V600E colorectal cancer. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2015 Nov 5-9; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2015;14(12 Suppl 2):Abstract nr C174.

As molecularly targeted agents assume a more prominent role in anticancer therapy there is a growing need to determine in a noninvasive manner whether the target is being engaged and to what extent such drug-target binding results in desirable effects. We address this need in the context of Hsp90, a target of significant value and one in critical need for such assessment tools, by combining a novel chemical tool selective for tumor Hsp90 with PET imaging and mathematical modeling. The chemical tool is [124I]-PU-H71, the iodine-124 radiolabeled analog of the potent Hsp90 inhibitor PU-H71, which can be administered in tracer quantities for PET imaging. The resulting diagnostic, PU-PET, has been optimized and validated preclinically in mouse models of cancer and then translated to the clinic. The exquisite design of this assay is based on three essential concepts as it relates to the target (Hsp90) as well as to the PET tracer (124I-PU-H71). First, the target is “oncogenic” Hsp90 and has been shown by numerous biochemical and pharmacokinetic studies to have a strong affinity for inhibitors and a very low koff resulting in selective and prolonged retention in tumor. Secondly, the tracer incorporates a 124I in place of the naturally occurring 127I in the structure of PU-H71 and therefore there is no change in the chemical structure. This feature in a PET tracer intended as a companion diagnostic is unprecedented and ensures that the PK properties are identical to the therapeutic agent (PU-H71). Finally, the radionuclide 124I has a four-day half-life and thus is well-suited to monitor the extended tumor retention profile observed for Hsp90 inhibitors. We here demonstrate that this PET assay informs on Hsp90 targeting in individual tumors in real time and provides accurate tumor drug concentrations for at least four chemically distinct Hsp90 drugs. In contrast, we find that plasma pharmacokinetics is not predictive of intratumor parameters and therefore provides limited value in estimating target engagement. Using PU-PET we demonstrate that at least one Hsp90 inhibitor exhibits tumor targeting and retention in humans, delivering and retaining therapeutic, micromolar, concentrations at safe doses. PU-PET is currently being evaluated in Phase 0/1 (NCT01269593) clinical trials as a noninvasive companion diagnostic to determine intratumoral concentration as well as to identify those patients who would best benefit from Hsp90 inhibitor therapy. This diagnostic assay is intended to be incorporated into future Phase 2 clinical trials in order to preselect those patients who would most likely benefit from Hsp90 inhibitor treatment. Citation Format: Tony Taldone, Nagavarakishore Pillarsetty, Mark PS Dunphy, John F. Gerecitano, Eloisi Caldas-Lopes, Brad Beattie, Radu I. Peter, Yanlong Kang, Anna Rodina, Pengrong Yan, Erica M. DaGama Gomes, Alexander Bolaender, Christina Pressl, Blesida Punzalan, Anson Ku, Thomas Ku, Smit Shah, Mohammad Uddin, Mei H. Chen, Elmer Santos, Jacek Koziorowski, Adriana Corben, Shanu Modi, Komal Jhaveri, Oscar Lin, Efsevia Vakiani, Yelena Janjigian, Pat Zanzonico, Clifford Hudis, Steven M. Larson, Jason S. Lewis, Gabriela Chiosis. Development of a noninvasive assay to determine drug concentration in tumor during hsp90 inhibitor therapy. [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 5444. doi:10.1158/1538-7445.AM2015-5444

11071 Background: The current mainstay of clinical molecular testing for advanced colorectal carcinoma (CRC) is mutation analysis for KRAS, NRAS, and BRAF to determine anti-EGFR therapy eligibility...

4110 Background: Patients with cancers of unknown primary (CUP) represent a heterogeneous population, and the frequency of actionable molecular alterations in their tumors remains unknown. These pa...

Non-Hodgkin lymphoma of T-cell lineage involving the breast is rare. We report on a 41-year-old woman with T-cell lymphoblastic lymphoma who presented with multiple bilateral breast masses. The patient was treated with intensive chemotherapy and med- iastinal and whole-brain irradiation. She remains in complete remission 24 months after diagnosis. The clinical, histologic, phenotypic, and cytogenetic features are described, with a review of the literature.

Hermansky-Pudlak syndrome (HPS) is a genetic disorder characterized by oculocutaneous albinism, a bleeding diathesis, and in a subset of patients, pulmonary fibrosis. Lung transplantation, the only curative therapy for pulmonary fibrosis, has not been previously reported as a successful treatment strategy for patients with HPS because the bleeding diathesis was thought to contraindicate major thoracic surgery. We successfully performed bilateral sequential lung transplantation in a patient with pulmonary fibrosis and HPS after transfusion of 6 units of platelets. Lung transplantation is a viable therapeutic option in patients with pulmonary fibrosis and only a mild bleeding diathesis associated with HPS.

57 Background: Esophagogastric (EG) cancer is a phenotypically heterogeneous disease. The Cancer Genome Atlas (TCGA) identified four distinct subsets: 1) Epstein Barr Virus (EBV) tumors with PIK3CA mutations, PD-L1/2 amplification (amp), 2) Tumors with Microsatellite instability (MSI-H), 3) chromosomally unstable (CIN) tumors with frequent amplifications, 4) chromosomally stable/diffuse type tumors with RHOA mutations. We explore the utility/feasibility of genomic profiling of EG tumors in routine clinical practice. Methods: Patients (pts) with metastatic EG adenocarcinoma undergoing treatment at MSKCC were consented for molecular testing under institutional protocol. Archival formalin fixed paraffin embedded (FFPE) samples were analyzed using an on-site 341 cancer-associated gene bait capture, next generation sequencing (NGS) assay. Results: Of 70 analyzed EG tumors, 66 (94%) harbored at least one genomic alteration, the most frequent being TP53 mutations (77%), HER2 amp (30%) and EGFR amp (10%). Alterations in PI3K/AKT/mTOR (9%) and G1-S1 cell cycle regulators (CDK12 (11%), CDKN2A (10%)) were also observed. A comparison with the TCGA results revealed an over-representation of the CIN subtype (65% vs 50% in TCGA). We found very few EBV or MSI tumors (3% each), with the remaining 29% being chromosomally stable. Data is reported in the clinical medical record and maintained in the MSKCC-internal cBioPortal for Cancer Genomics ( http://cbioportal.org ) (Gao, et al.). The portal is a web resource for exploring, visualizing, and analyzing multidimensional cancer genomics data and when available, to link these data to therapeutic interventions and clinical outcomes. Conclusions: CIN tumors with frequent amplifications represent majority of metastatic EG cancer at our institution. Optimal development of target-specific therapy for EG tumors will require genomic characterization. Comprehensive molecular profiling is feasible in routine clinical practice and has created a roadmap for pt stratification and genome-guided trial development.

59 Background: Trastuzumab combined with chemotherapy is the standard of care for pts with HER2+ EG cancer. Resistance to trastuzumab clearly emerges in this population. Afatinib, a potent ErbB Family Blocker, induced tumor regression in MSKCC HER2+ patient derived xenografts (PDX). This study assesses safety and preliminary efficacy of afatinib in patients with trastuzumab refractory EG cancer. Methods: Pts with HER2+ (IHC 3+ or FISH>2.0) EG adenocarcinoma, after progression on trastuzumab, received oral afatinib 40 mg daily. Archival pre-trastuzumab tissue, tumor biopsy after progression on trastuzumab and after 1 week on afatinib is mandated on protocol for next generation sequencing (NGS), proteomics and establishment of PDX. The primary endpoint-overall clinical benefit at 4 months: stable disease (SD) or partial response (PR). Results: 20 pts treated with afatinib; median age 61, KPS 80; median 2 (1 to 4) prior trastuzumab regimens, 67% of tumors IHC3+; 33% IHC2+/FISH>2.0. Common adverse events included: rash or dry skin (Grade 1/2:80%), diarrhea (Grade 1/2:60%), nausea/vomiting (grade 1/2:40%) fatigue (grade1/2: 25%). To date, 19 pts evaluable for response, 2 PRs and 6 SD, 42% disease stabilization rate (PR+SD) at 4months (4 to 13 mos). PDXs established from biopsies of 7 pts. EGFR amplification was detected in the tumor of 2 pts with PRs and 1 of 6 pts with SD. Recurrent PIK3CA, ERBB3 and MTORmutations were observed. Conclusions: Afatinib shows clinical efficacy and is well tolerated in patients with trastuzumab refractory, heavily pretreated EG cancer. Enrollment has now begun in an afatinib + trastuzumab cohort. Efforts to elucidate the mechanisms of trastuzumab resistance including validation of potential drivers of trastuzumab resistance using HER2+ PDXs are ongoing. Updated molecular and clinical data will be presented. Clinical trial information: NCT01522768.

63 Background: Trastuzumab-based therapy is the standard therapeutic approach for patients with metastatic HER2+ esophagogastric (EG) tumors. While trastuzumab prolongs survival in this population, responses are rarely complete and resistance invariably develops. Loss of HER2 and presence of co-occurring molecular alterations may impact the efficacy of HER2 targeted agents in second line setting. Methods: We reviewed clinical and pathologic data of patients (pts) with metastatic HER2+ (IHC 3+ or FISH >2.0) EG adenocarcinoma undergoing trastuzumab/chemotherapy treatment at MSKCC. Samples with ample tissue were analyzed using an on-site 341 cancer-associated gene bait capture, next generation sequencing (NGS) assay. When available, biopsy at the time of disease progression on trastuzumab was tested for HER2 by IHC and FISH. Results: Eighty four pts with Stage IV HER2+ EG adenocarcinoma (57 IHC 3+, 27 IHC2+/FISH+) treated with trastuzumab with chemotherapy. Median progression free survival on 1stline trastuzumab therapy 9.4 months (mos) [95%CI: 6.9-13.3 mos]. Median overall survival 20.3 mos [95%CI: 14.7-22.4 mos]. Post-trastuzumab biopsy available in 23 of 84 (27%) pts, of those 35% (8 of 23) lost HER2 positivity (4-IHC 0, 4 FISH negative). NGS performed on 24 of 84 (28%) samples. Alterations were observed in EGFR (13%), TP53 mut (92%), cell cycle mediators such as cyclin dependent kinases (42%) and the phosphoinositide 3-kinase/AKT/mTOR axis (21%). Conclusions: Loss of HER2 expression occurs in patients with HER2+ EG cancer treated with trastuzumab and presents a possible mechanism for trastuzumab resistance. Our data suggest the need for repeat biopsies to accurately determine appropriate use of second-line HER2 directed therapy.

611 Background: BRAF mutant metastatic colorectal cancer (mCRC) is an aggressive subset of colorectal cancer that exhibits minimal response to selective RAF inhibitors. Preclinical data suggest that epidermal growth factor receptor (EGFR) reactivation with RAF inhibition attenuates the efficacy of RAF inhibitors in mCRC and that combined EGFR and RAF inhibition may be a promising therapeutic strategy. Methods: We undertook a pilot trial to assess the response rate and safety of the combination of the selective RAF inhibitior vemurafenib and anti-EGFR antibody panitumumab in patients with BRAF mutant mCRC. Patients received panitumumab 6 mg/kg IV every 14 days starting on day 1 and vemurafenib 960 mg orally twice daily continuously starting on day 8, with treatment staggered for planned correlative studies. Results: Fifteen patients received treatment. Median age was 62 years (range 22-83 years), seven patients (47%) were male, and 11 patients (73%) had a right-sided primary tumor. Performance status was ECOG 0 in four patients (27%) and ECOG 1 in 11 patients (73%). All patients had progressed through at least one standard treatment regimen, and eight patients (53%) had received previous fluoropyrimidine, oxaliplatin, and irinotecan chemotherapy. Acneiform rash (all grade 1 or 2) (53%), fatigue (53%), and arthralgias (40%) were the most frequently observed treatment-related adverse events. Treatment response was assessed in 12 patients because two patients died from disease progression before the first scan and one patient withdrew consent soon after starting treatment. Two patients (13%) had confirmed partial responses (100% and 64% regression) lasting 40 and 24 weeks, respectively. Eight patients (53%) had stable disease (SD) with tumor regression of >15% by RECIST measurement in six of these patients, including two of whom achieved stable disease lasting over six months. Conclusions: Combined RAF and EGFR inhibition is well tolerated and leads to tumor regression in a subset of patients with BRAF mutant mCRC. Planned correlative studies will evaluate degree of pathway inhibition and reactivation of other upsteam pathways with vemurafenib and panitumumab treatment. Clinical trial information: NCT01791309.

Background: Trastuzumab (T) combined with chemotherapy has been the standard of care for pts with HER2+ EG cancer. Resistance to T is now emerging in this population. Afatinib (A), a potent ErbB Family Blocker, induced nearly complete tumor regression in MSKCC HER2+ patient derived xenografts (PDX). We report the initial results of a phase II study of afatinib in patients with T refractory EG cancer. Methods: Pts with HER2+ (IHC 3+ or FISH>2.0) EG cancer -progressive on trastuzumab -received A 40 mg. Archival pre-T tissue, tumor biopsy after progression on T and after 1 week on A mandated on protocol. The primary endpoint-overall disease control: stable disease (SD) or partial response (PR). Results: 14 pts treated with A; median duration 5.1 mos (1.7 to 12.1 mos), median 2 (1 to 4) prior T regimens, 64% of tumors IHC3+; 36% IHC2+/FISH>2.2. Adverse events included: diarrhea (Grade 1/2:69%), fatigue (Grade1/2: 54%), rash (Grade 1/2:54%), mucositis (Grade1: 23%), paronychia (Grade 1/2:15%). 4 of 14 pts (28%) with disease control (PR or SD); including 1 pt with confirmed PR - a durable 75% regression of biopsy proven metastases. Median OS 6.6 mos (1.9 to NR). PDXs established from biopsies of T refractory tumors of 5 pts. EGFR amplification was detected in the tumor of the patient with PR on afatinib, suggesting EGFR amplification as a predictor of response to afatinib. High level of HER2 amplification was retained in post-trastuzumab resistance sample suggesting ongoing dependence on HER2. PIK3CA mutations were observed in tumors of 33% (2 of 6) patients, ERBB3 mutations in 33% cases (2 of 6), and MTOR or FBXW7 mutations in 50% (3 of 6) patients. Conclusions: Afatinib shows clinical efficacy in patients with T refractory EG cancer. The study met the criteria for expansion of the accrual based on original Simon's minimax two-stage design. Efforts to elucidate the mechanisms of T resistance including validation of potential drivers of T resistance using HER2+ PDXs are ongoing. Updated molecular and clinical data will be presented. Citation Format: Yelena Y. Janjigian, Tooba Imtiaz, David H. Ilson, David B, Solit, Michael F. Berger, Efsevia Vakiani. A phase II study of afatinib (A) in patients (pts) with metastatic human epidermal growth factor receptor (HER2)-positive trastuzumab (T) refractory esophagogastric (EG) cancer. [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 CT228. doi:10.1158/1538-7445.AM2014-CT228

4059 Background: Individual EG cancer subtypes have heterogeneous tumor characteristics and clinical outcome, making EG adenocarcinoma a complex disease to treat. Cytotoxic agents are applied to al...

e15017 Background: Trastuzumab, approved by the FDA, has been the standard of care for pts with HER2-positive EG cancer. Resistance to trastuzumab is now emerging in this population. Afatinib, an oral inhibitor of EGFR, HER2, and HER4 has potent single agent activity in HER2-positive EG cancer NCI-N87 and MSKCC patient derived xenografts (Janjigian JNM 2013). We report the initial results of a phase II study of afatinib in patients with trastuzumab refractory EG cancer. Methods: Pts with HER2 positive (IHC 3+ or FISH>2.0) metastatic EG adenocarcinoma, following failure of at least one trastuzumab/chemotherapy regimen received afatinib 40 mg daily. Archival tissue from pre-trastuzumab biopsy, a new biopsy prior to the start of therapy and after 1 wk of afatinib are mandated. The primary endpoint-overall clinical benefit at 4 months: stable disease (SD), complete response (CR), or partial response (PR) by RECIST 1.1. Results: Nine patients treated with afatinib; median follow up 2.7mos (0.5 to 5.3mos). Median age 62, KPS 80, 6 males, 56% IHC3+; 44% IHC1+/2+/FISH>2.0. Number of prior trastuzumab containing regimens: median 2 (1 to 4). The following treatment emergent adverse events were observed: nausea/vomiting (Grade 1/2: 22%), diarrhea (Grade 1/2:67%), fatigue (Grade1/2: 33%), rash (Grade 1/2:44%), anorexia (Grade 1/2:33%,Grade 3:11%), mucositis (Grade1/2: 11%), paronychia/nail loss (Grade 1/2:11%). To date, 7 pts evaluable for response, 3 of 7 patients (43%) derived clinical benefit; 1 pt (14%) with ongoing RECIST 1.1 confirmed PR - a durable 50% regression of biopsy proven metastases in lung and lymph nodes at 5.3 mo. A second patient had 20% tumor regression in biopsy proven liver metastasis, 3.6 mos disease stabilization. A third patient experienced 4.7 mos disease stabilization and regression of biopsy proven skin metastasis. Conclusions: Single agent afatinib shows clinical efficacy in patients with trastuzumab refractory EG cancer. The study has been expanded to accrue additional patients. Efforts to elucidate the mechanisms of trastuzumab resistance in EG cancer are ongoing. Updated molecular and clinical data will be presented. Clinical trial information: NCT01522768.

510 Background: In patients with resected CRLM, mutant (MUT) KRAS may confer a worse prognosis than wild-type (WT) KRAS (Karagkounis et al., ASCO 2012, abs 3616; Kemeny et al., ASCO 2013, abs 3609). We analyzed the impact of KRAS on the outcomes of patients with unresectable CRLM treated with hepatic arterial infusion (HAI) + systemic chemotherapy. Methods: Median overall survival (OS) and progression-free survival (PFS) were estimated by Kaplan Meier methods. The log rank test was used to examine the association of patient demographics and disease-related factors including KRAS mutation status with OS and PFS. Cox proportion hazards model was used to examine the association of liver resection with survival outcomes by treating liver resection as a time dependent covariate. Results: Of 93 patients: 59 male, 34 female; 77 Caucasian, 16 non-Caucasian; 66 were age < 60 years, 27 were age > 60 years; 70 were KRAS WT and 23 were KRAS MUT; 59 had chemotherapy pre-HAI pump placement and 53 subsequently underwent liver resection. Median PFS and OS were 13.3 months and 45.7 months, respectively. Age, sex and race were not associated with PFS or OS. Univariate analysis of the impact of KRAS, pre-HAI chemotherapy, and subsequent liver resection on PFS and OS is presented in the Table. Multivariate analysis including important variables did not change outcome. Conclusions: In patients with unresectable CRLM treated with HAI and systemic chemotherapy, overall survival tended to be improved in KRAS WT vs MUT patients. [Table: see text]

3609 Background: There are conflicting results regarding the influence of KRAS mutation status and outcome in patients (pts) with colorectal cancer. A recent report suggested worse outcome in KRAS mutated (MUT) pts who underwent resection of hepatic metastases (Karagkounis et al, ASCO 2012). Methods: Recurrence patterns and survival were evaluated in 169 patients who had undergone resection of liver metastases, then received adjuvant hepatic arterial infusion and systemic chemotherapy, and for whom KRAS data were available. Kaplan-Meier methods were used to estimate recurrence free survival (RFS) and overall survival (OS). Log-rank test was used to determine whether survival functions differed by KRAS mutation status. Cumulative incidence function was used to estimate the probability of time from adjuvant therapy to bone, brain, lung and liver metastases separately. Mutations in KRAS (codons 12, 13) were detected using the iPLEX assay (Sequenom, Inc). Results: Median follow-up for the entire cohort was 38.8 months. 118 were KRAS wildtype (WT), and 51 were KRAS MUT (45 G12, 5 G13, 1 K117N). The 3 year RFS was 48% [95%CI: 37-58%] for KRAS WT pts and 30% [15-44%] for MUT pts (p

398 Background: There have been conflicting results about whether KRAS mutation influences outcome in patients (pts) with colorectal cancer. In pts who underwent liver resection, Karagkounis reported a worse recurrence and survival in KRAS mutated (MUT) patients (ASCO 2012, abs 3616). Methods: In 105 pts who underwent liver resection and received adjuvant (adj) hepatic arterial infusion and systemic chemotherapy and in whom KRAS data was available, we evaluated recurrence patterns and survival. Correlation between KRAS and clinical factors such as prior chemotherapy, post operative CEA, clinical risk score, and stage at diagnosis was evaluated using Fisher’s exact test and the Wilcoxon rank sum test. Kaplan-Meier methods were used to estimate median overall recurrence free survival (RFS) and overall survival (OS) at 4 years. Log-rank test was used to determine whether survival functions differed by KRAS mutation status. Cumulative incidence function was used to estimate the probability of time from adj therapy to bone, brain, lung and liver metastases separately. Results: Of 105 patients, 76 were KRAS wildtype (WT), and 29 were KRAS MUT (26-G12 and 3-G13). The median RFS was 26 months for KRAS WT pts and 15 months for KRAS MUT pts (p=0.08). OS at 4 years was 88% [95% CI: 78%-94%] for KRAS WT and 78% [95% CI: 57%-90%] for KRAS MUT pts (p= 0.15). Cumulative incidence of developing bone, brain, lung, and liver metastases by 2 years is presented in the Table. The cumulative incidence of bone and brain metastases at 2 years was 0% and 0% in KRAS WT pts versus 16.4% [95% CI: 1.1%-31.7%] and 4.7% [95% CI: 0%-14.1%] in KRAS MUT pts (Table). There was no association between clinical factors and KRAS status. Conclusions: KRAS MUT pts appeared to have worse OS and RFS, although we were unable to show a significant difference between KRAS WT and MUT for OS and RFS. In addition, cumulative incidence of bone and brain metastases at 2 years appeared to be higher for KRAS MUT pts as compared to WT pts. Results are based on small sample size and further investigation is needed. [Table: see text]

95 Background: Gastric cancer is a heterogeneous disease that may be subdivided into distinct subtypes—proximal/gastroesophageal (GE) junction, diffuse/signet ring type, and distal gastric cancer/intestinal type—based on histopathologic and anatomic criteria. Each subtype is associated with unique epidemiology and gene expression. Human epidermal growth factor receptor (HER2) is a validated treatment target in gastric cancer. For patients with metastatic disease, the available cytotoxic agents are applied indiscriminately to all disease subtypes, and with only modest success. The purpose of this study is to establish xenograft models from gastric cancer subtypes to improve our understanding of disease heterogeneity and develop therapies geared for each subtype of gastric cancer. Methods: Fresh specimens obtained from resected primary or metastatic tumors under aseptic conditions. 1 g tumor samples injected SQ into flanks of NSG mice. Xenografts established after 5 passages and maintained by serial transplantation into new mice. Cell cultures established after 5 in vitro passages; cell lines after 15 passages Results: To date, 66 tumor samples have been implanted from which 16 xenografts have been established. The table below summarizes the results. Single-agent afatinib (pan-ErbB inhibitor) demonstrated antitumor activity in an HER2-positive xenograft established from MSKCC patient’s tumor harvested from a skin metastasis. Conclusions: We have established xenograft models of gastric cancer. In vivo testing of afatinib showed a reduction of tumor growth of HER2-positive gastric cancer. These models provide a platform to study potential therapeutics for esophagogastric cancer to further validate difference in their biology and guide rational design of clinical trials. [Table: see text]

Background In colorectal cancer (CRC), the third most common cause of cancer and cancer death for both men and women in the USA, the steps necessary for carcinogenesis have been well defined. However, the genetic changes necessary for tumor evolution to metastasis are not as well elucidated. Therefore, we searched for the presence of mutations in key cancer genes in primary and metastatic colorectal cancer to determine whether primary or metastatic tissue is ideal for biomarker analysis and to identify putative biomarkers.

Background: B-cell post transplant lymphoproliferative disorders (PTLDs) encompass a diverse group of entities, the majority representing EBV-driven lymphoproliferations, which arise in the setting of iatrogenic immunosuppression. Their pathogenesis, especially the genetic relationship of PTLD with other types of B-cell non-Hodgkin lymphomas (B-NHLs), is not well understood and the association of polymorphic PTLD (P-PTLD) with monomorphic PTLD (M-PTLD) is presently unclear. Thus, in order to address these issues we analyzed gene expression profiles of PTLD and compared them with those derived from other types of B-NHL, normal B-cell subsets, and B-cell derived cell lines. Material and methods: Paraffin embedded and H&E stained sections were used for morphologic analysis and PTLD were classified according to the WHO classification. Phenotypic characterization was performed using a comprehensive panel of antibodies and in situ hybridization for EBER. Frozen tissue from PTLD, different B-NHL, purified normal B-cell subsets, EBV-transformed lymphoblastoid cell lines (LCLs) and multiple myeloma cell lines, was used to generate complementary RNA (cRNA) that was hybridized to HGU95 arrays (Affymetrix). Gene expression data were analyzed using unsupervised and supervised clustering algorithms and classifiers were generated to determine the relationship between PTLD and cells corresponding to different stages of mature B-cell development. Results: The 12 PTLD analyzed represented an infectious mononucleosis-like (IM-like) lesion, 5 P-PTLD, and 6 M-PTLD. All P-PTLD and 5 M-PTLD had late-germinal center (GC)/post-GC phenotypes and 8 PTLD, including the IM-like lesion, were EBV+, while 4 PTLD were EBV−. The expression profiles of late GC/post GC PTLD appeared homogeneous and distinct from other B-NHL, however no segregation of P-PTLD and M-PTLD or EBV+ and EBV− PTLD was noted. Surprisingly, on supervised analysis, only 4 genes were expressed at higher levels in PTLD compared to B-NHL and normal B-cell subsets (BLIMP-1, XBP-1, IFITM3, PCMT1) and only 2 genes were differentially upregulated in EBV+ PTLD (CD27 ligand, MTDH). The expression profiles of PTLD appeared most similar to LCLs. Conclusions: B-cell PTLDs of late-GC/post-GC phenotype represent a distinct type of B-NHL, which are possibly derived from activated B-cells. Despite morphologic distinctions, P-PTLD and M-PTLD have overlapping genetic profiles suggesting disease heterogeneity within different categories.