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Breakdown of RET and ROS1 fusion positive patients

S1. Generation of MCF-10A isogenic cells via TP53 knockout and AKT1 E17K knock-in. S2. Frequent co-occurrence of AKT1, TP53 and CDH1 mutations in breast cancers. S3. TP53 CRISPR knockout in MCF-10A cells. S4. Phosphorylation of the AKT1 effector PRAS40 was AKT-dependent in MCF-10A p53ko/E17K cells. S5. Immunofluorescence using a pT308 specific AKT1 antibody of MCF-10A cells following lentiviral infection with V5 tagged (V5 tag) wildtype (WT) or E17K mutant AKT1. S6. Knock-in of the AKT1 E17K mutation did not enhance sensitivity to the pan-AKT kinase inhibitor AZD5363 or the allosteric pan-AKT inhibitor MK2206 in 2Dculture conditions. S7. Survey of previously postulated mechanisms for AKT1-mediated inhibition of cell migration in breast cancer cells. S8. CDH1 promoter methylation status in the MCF-10A isogenic cells. S9. β-catenin interacts with the kinase domain of AKT1. S10. Expression of AKT1 E17K decreased phosphorylation of AKT2 in MCF-10A cells. S11. AKT2 knockdown induces E-cadherin expression in MCF-10A p53ko cells. S12. Model of the mechanism of paradoxical inhibition of cell migration by activated AKT1. Table S1. List of oligonucleotide sequences Table S2. List of antibodies Table S3. List of plasmids

Co-occurring Level 1-3 alterations by MSK-IMPACT in 52 patients

Types of Clinical trials patients enrolled to according to level 1-4 and UMD assigned samples

Supplementary Table S1: List of actionable genes and potential matched therapy Supplementary Table S2: List of co-occurring Level 1-4 mutations Supplementary Table S3: EGFR mutations identified and associated therapy Supplementary Table S4: List of 410 genes in MSK-IMPACT assay

Breakdown of MAP2K1, RAF1, ARAF, FGFR3-TACC3 fusion and CDKN2A loss patients

Mutational activation of the PI3K/AKT pathway is among the most common pro-oncogenic events in human cancers. The clinical utility of PI3K and AKT inhibitors has, however, been modest to date. Here, we used CRISPR-mediated gene editing to study the biological consequences of AKT1 E17K mutation by developing an AKT1 E17K–mutant isogenic system in a TP53-null background. AKT1 E17K expression under the control of its endogenous promoter enhanced cell growth and colony formation, but had a paradoxical inhibitory effect on cell migration and invasion. The mechanistic basis by which activated AKT1 inhibited cell migration and invasion was increased E-cadherin expression mediated by suppression of ZEB1 transcription via altered β-catenin subcellular localization. This phenotypic effect was AKT1-specific, as AKT2 activation had the opposite effect, a reduction in E-cadherin expression. Consistent with the opposing effects of AKT1 and AKT2 activation on E-cadherin expression, a pro-migratory effect of AKT1 activation was not observed in breast cancer cells with PTEN loss or expression of an activating PIK3CA mutation, alterations which induce the activation of both AKT isoforms. The results suggest that the use of AKT inhibitors in patients with breast cancer could paradoxically accelerate metastatic progression in some genetic contexts and may explain the frequent coselection for CDH1 mutations in AKT1-mutated breast tumors.Implications:AKT1 E17K mutation in breast cancer impairs migration/invasiveness via sequestration of β-catenin to the cell membrane leading to decreased ZEB1 transcription, resulting in increased E-cadherin expression and a reversal of epithelial–mesenchymal transition.

Patient 1 Concurrent EGFR and KRAS mutations in a patient identified by MSK-IMPACT

Median number of mutations in samples sequenced by MSK-IMPACT in patients with a Level 1-4 alteration or assigned to the unknown mitogenic driver cohort.

Patient 2 Concurrent EGFR and KRAS mutations in a patient identified by MSK-IMPACT

Precision oncology relies on the accurate molecular characterization of individual patients with cancer at the time of treatment initiation. However, tumor molecular profiles are not static, and cancers continually evolve because of ongoing mutagenesis and clonal selection. Here, we performed genomic analyses of primary tumors, metastases, and plasma collected from individual patients to define the concordance of actionable genomic alterations and to identify drivers of metastatic disease progression. We observed a high degree of discordance of actionable genomic alterations, with 23% discordant between primary and metastatic disease sites. Among chromatin-modifying genes, ARID1A mutations, when discordant, were exclusive to the metastatic tumor samples. Our findings indicate that the high degree of lesion-to-lesion genomic heterogeneity may be a barrier to precision oncology approaches for bladder cancer and that circulating tumor DNA profiling may be preferred to tumor sequencing for a subset of patients.

Cancers arising from the bladder urothelium often exhibit lineage plasticity with regions of urothelial carcinoma adjacent to or admixed with regions of divergent histomorphology, most commonly squamous differentiation. To define the biologic basis for and clinical significance of this morphologic heterogeneity, here we perform integrated genomic analyses of mixed histology bladder cancers with separable regions of urothelial and squamous differentiation. We find that squamous differentiation is a marker of intratumoral genomic and immunologic heterogeneity in patients with bladder cancer and a biomarker of intrinsic immunotherapy resistance. Phylogenetic analysis confirms that in all cases the urothelial and squamous regions are derived from a common shared precursor. Despite the presence of marked genomic heterogeneity between co-existent urothelial and squamous differentiated regions, no recurrent genomic alteration exclusive to the urothelial or squamous morphologies is identified. Rather, lineage plasticity in bladder cancers with squamous differentiation is associated with loss of expression of FOXA1, GATA3, and PPARG, transcription factors critical for maintenance of urothelial cell identity. Of clinical significance, lineage plasticity and PD-L1 expression is coordinately dysregulated via FOXA1, with patients exhibiting morphologic heterogeneity pre-treatment significantly less likely to respond to immune checkpoint inhibitors.

Mutational activation of the PI3K/AKT pathway is among the most common pro-oncogenic events in human cancers. The clinical utility of PI3K and AKT inhibitors has, however, been modest to date. Here, we used CRISPR-mediated gene editing to study the biological consequences of AKT1 E17K mutation by developing an AKT1 E17K–mutant isogenic system in a TP53-null background. AKT1 E17K expression under the control of its endogenous promoter enhanced cell growth and colony formation, but had a paradoxical inhibitory effect on cell migration and invasion. The mechanistic basis by which activated AKT1 inhibited cell migration and invasion was increased E-cadherin expression mediated by suppression of ZEB1 transcription via altered β-catenin subcellular localization. This phenotypic effect was AKT1-specific, as AKT2 activation had the opposite effect, a reduction in E-cadherin expression. Consistent with the opposing effects of AKT1 and AKT2 activation on E-cadherin expression, a pro-migratory effect of AKT1 activation was not observed in breast cancer cells with PTEN loss or expression of an activating PIK3CA mutation, alterations which induce the activation of both AKT isoforms. The results suggest that the use of AKT inhibitors in patients with breast cancer could paradoxically accelerate metastatic progression in some genetic contexts and may explain the frequent coselection for CDH1 mutations in AKT1-mutated breast tumors. Implications: AKT1 E17K mutation in breast cancer impairs migration/invasiveness via sequestration of β-catenin to the cell membrane leading to decreased ZEB1 transcription, resulting in increased E-cadherin expression and a reversal of epithelial–mesenchymal transition.

Cardiac sarcoma is a rare malignant tumor with undefined genetic mutations and no targeted therapy. Here in one rare case of undifferentiated cardiac intimal sarcoma (IS), a next-generation sequencing based assay, MSK-IMPACT (Memorial Sloan Kettering - Integrated Mutation Profiling of Actionable Cancer Targets), identified a somatic, activating mutation in PDGFRB, along with amplification of PDGFRA. This E472D mutation of PDGFRB was discovered for the first time in IS. These findings suggest that concurrent aberrant PDGFRA and PDGFRB signaling may be a diagnostic biomarker and molecular therapeutic target of IS of the heart.

Tumor genetic testing is standard of care for patients with advanced lung adenocarcinoma, but the fraction of patients who derive clinical benefit remains undefined. Here, we report the experience of 860 patients with metastatic lung adenocarcinoma analyzed prospectively for mutations in >300 cancer-associated genes. Potentially actionable genetic events were stratified into one of four levels based upon published clinical or laboratory evidence that the mutation in question confers increased sensitivity to standard or investigational therapies. Overall, 37.1% (319/860) of patients received a matched therapy guided by their tumor molecular profile. Excluding alterations associated with standard-of-care therapy, 14.4% (69/478) received matched therapy, with a clinical benefit of 52%. Use of matched therapy was strongly influenced by the level of preexistent clinical evidence that the mutation identified predicts for drug response. Analysis of genes mutated significantly more often in tumors without known actionable mutations nominated STK11 and KEAP1 as possible targetable mitogenic drivers. Significance: An increasing number of therapies that target molecular alterations required for tumor maintenance and progression have demonstrated clinical activity in patients with lung adenocarcinoma. The data reported here suggest that broader, early testing for molecular alterations that have not yet been recognized as standard-of-care predictive biomarkers of drug response could accelerate the development of targeted agents for rare mutational events and could result in improved clinical outcomes. Cancer Discov; 7(6); 596–609. ©2017 AACR. See related commentary by Liu et al., p. 555. This article is highlighted in the In This Issue feature, p. 539

AKT- a key molecular regulator of PI-3K signaling pathway, is somatically mutated in diverse solid cancer types, and aberrant AKT activation promotes altered cancer cell growth, survival, and metabolism1–8. The most common of AKT mutations (AKT1 E17K) sensitizes affected solid tumors to AKT inhibitor therapy7,8. However, the pathway dependence and inhibitor sensitivity of the long tail of potentially activating mutations in AKT is poorly understood, limiting our ability to act clinically in prospectively characterized cancer patients. Here we show, through population-scale driver mutation discovery combined with functional, biological, and therapeutic studies that some but not all missense mutations activate downstream AKT effector pathways in a growth factor-independent manner and sensitize tumor cells to diverse AKT inhibitors. A distinct class of small in-frame duplications paralogous across AKT isoforms induce structural changes different than those of activating missense mutations, leading to a greater degree of membrane affinity, AKT activation, and cell proliferation as well as pathway dependence and hyper-sensitivity to ATP-competitive, but not allosteric AKT inhibitors. Assessing these mutations clinically, we conducted a phase II clinical trial testing the AKT inhibitor capivasertib (AZD5363) in patients with solid tumors harboring AKT alterations (NCT03310541). Twelve patients were enrolled, out of which six harbored AKT1-3 non-E17K mutations. The median progression free survival (PFS) of capivasertib therapy was 84 days (95% CI 50-not reached) with an objective response rate of 25% (n = 3 of 12) and clinical benefit rate of 42% (n = 5 of 12). Collectively, our data indicate that the degree and mechanism of activation of oncogenic AKT mutants vary, thereby dictating allele-specific pharmacological sensitivities to AKT inhibition.

529 Background: Large-scale efforts have sought to define the genomic landscape of urothelial carcinomas of the bladder with the goal of identifying novel therapeutic targets. Many bladder cancers harbor mutations in genes that regulate chromatin state, such as KDM6A, ARID1A and KMT2D. There remains uncertainty as to the timing at which alterations in chromatin modifying genes (CMG) arise during the evolution of urothelial cancer. Methods: We leveraged a prospective genomic profiling initiative to characterize driver alterations in urothelial cancer. To define the timing at which mutations arose during disease pathogenesis, we performed whole exome (WES) or targeted sequencing analysis of matched pairs of primary and metastatic tumors. Results: CMG mutations were identified in 76% of UC samples in the prospective MSK-IMPACT tumor sequencing cohort (N=1057); most frequent in KDM6A (31%), KMT2D (28%) and ARID1A (27%). Comparison of primary low-grade (N=65), high-grade (N=742) and metastatic (N=250) samples revealed KDM6A, FGFR3 and KMT2C were more frequently mutated in low-grade tumors. WES and targeted sequencing of 63 matched pairs demonstrate a high degree of concordance among likely oncogenic mutations. Notably, 100% (18/18) of pairs were concordant for mutations in KDM6A suggesting that, when present KDM6A mutations arise early during tumor development. Mutations in ARID1A were present only in the metastatic samples of a subset of tumors (29%) suggesting that ARID1A mutations arise later in disease pathogenesis. Several additional oncogenic drivers were found in only the metastatic sample ( FGFR3, TSC1, PIK3CA) of select tumor pairs. Conclusions: Primary and metastatic pairs were largely concordant for known and likely oncogenic mutations. Evolutionary analysis of sequencing data suggested that KDM6A mutations arise early in tumor development whereas ARID1A mutations were enriched and present only in the metastatic samples of a subset of patients. Despite the high frequency of FGFR3 mutations in low grade tumors, discordance of FGFR3 mutational status was observed in small fraction of patients suggesting that profiling of metastatic tumors or cell free DNA would be preferable to identify patients for FGFR inhibitor therapy.

Mutational hotspots indicate selective pressure across a population of tumor samples, but their prevalence within and across cancer types is incompletely characterized. An approach to detect significantly mutated residues, rather than methods that identify recurrently mutated genes, may uncover new biologically and therapeutically relevant driver mutations. Here we developed a statistical algorithm to identify recurrently mutated residues in tumour samples. We applied the algorithm to 11,119 human tumors, spanning 41 cancer types, and identified 470 hotspot somatic substitutions in 275 genes. We find that half of all human tumors possess one or more mutational hotspots with widespread lineage-, position-, and mutant allele-specific differences, many of which are likely functional. In total, 243 hotspots were novel and appeared to affect a broad spectrum of molecular function, including hotspots at paralogous residues of Ras-related small GTPases RAC1 and RRAS2. Redefining hotspots at mutant amino acid resolution will help elucidate the allele-specific differences in their function and could have important therapeutic implications.

Plasmacytoid bladder cancer is an aggressive histologic variant with a high risk of disease-specific mortality. Using whole-exome and targeted sequencing, we find that truncating somatic alterations in the CDH1 gene occur in 84% of plasmacytoid carcinomas and are specific to this histologic variant. Consistent with the aggressive clinical behavior of plasmacytoid carcinomas, which frequently recur locally, CRISPR/Cas9-mediated knockout of CDH1 in bladder cancer cells enhanced cell migration.

Cardiac sarcoma is a rare malignant tumor with undefined genetic mutations and no targeted therapy. Here in one rare case of undifferentiated cardiac intimal sarcoma (IS), a next-generation sequencing based assay, MSK-IMPACT (Memorial Sloan Kettering - Integrated Mutation Profiling of Actionable Cancer Targets), identified a somatic, activating mutation in PDGFRB, along with amplification of PDGFRA. This E472D mutation of PDGFRB was discovered for the first time in IS. These findings suggest that concurrent aberrant PDGFRA and PDGFRB signaling may be a diagnostic biomarker and molecular therapeutic target of IS of the heart.

Purpose Owing to its exquisite chemotherapy sensitivity, most patients with metastatic germ cell tumors (GCTs) are cured with cisplatin-based chemotherapy. However, up to 30% of patients with advanced GCT exhibit cisplatin resistance, which requires intensive salvage treatment, and have a 50% risk of cancer-related death. To identify a genetic basis for cisplatin resistance, we performed whole-exome and targeted sequencing of cisplatin-sensitive and cisplatin-resistant GCTs. Methods Men with GCT who received a cisplatin-containing chemotherapy regimen and had available tumor tissue were eligible to participate in this study. Whole-exome sequencing or targeted exon-capture–based sequencing was performed on 180 tumors. Patients were categorized as cisplatin sensitive or cisplatin resistant by using a combination of postchemotherapy parameters, including serum tumor marker levels, radiology, and pathology at surgical resection of residual disease. Results TP53 alterations were present exclusively in cisplatin-resistant tumors and were particularly prevalent among primary mediastinal nonseminomas (72%). TP53 pathway alterations including MDM2 amplifications were more common among patients with adverse clinical features, categorized as poor risk according to the International Germ Cell Cancer Collaborative Group (IGCCCG) model. Despite this association, TP53 and MDM2 alterations predicted adverse prognosis independent of the IGCCCG model. Actionable alterations, including novel RAC1 mutations, were detected in 55% of cisplatin-resistant GCTs. Conclusion In GCT, TP53 and MDM2 alterations were associated with cisplatin resistance and inferior outcomes, independent of the IGCCCG model. The finding of frequent TP53 alterations among mediastinal primary nonseminomas may explain the more frequent chemoresistance observed with this tumor subtype. A substantial portion of cisplatin-resistant GCTs harbor actionable alterations, which might respond to targeted therapies. Genomic profiling of patients with advanced GCT could improve current risk stratification and identify novel therapeutic approaches for patients with cisplatin-resistant disease.

Observation of tongue coating, a foundation for clinical diagnosis and treatment in traditional Chinese medicine (TCM), is a major indicator of the occurrence, development and prognosis of disease. The biological basis of tongue diagnosis and relationship between the types and microorganisms of tongue coating remain elusive. Thirteen chronic erosive gastritis (CEG) patients with typical yellow tongue coating (YTC) and ten healthy volunteers with thin white tongue coating (WTC) were included in this study. Patients were provided a 2-course targeted treatment of a herbal medicine Ban Xia Xie Xin decoction, traditionally prescribed for CEG patients with YTC, to evaluate the relationship between tongue coating microbiota and diagnosis of CEG with typical YTC. The tongue coating segregation structure was determined using Illumina Miseq sequencing of the V4–V5 region of the 16S ribosomal RNA gene. Bacillus was significantly observed only in CEG patients with YTC, but not in patients who received the decoction. YTC (n = 22) and WTC (n = 29) samples were collected for bacterial culturing to illustrate the relationship between Bacillus and YTC. The Bacillus positivity rate of YTC samples was 72.7%; Bacillus was not observed in WTC samples. In conclusion, Bacillus was strongly associated with YTC.

To prospectively investigate the clinical efficacy of using diffuse optical tomography (DOT) and ultrasonographic (US) localization with conventional US to differentiate malignant solid breast lesions from those that are benign.The study was approved by the institutional review board and all patients provided written informed consent. One hundred two consecutive women (mean age, 43 years; range, 18-86 years) who were referred for open biopsy with 136 breast lesions underwent conventional US and DOT with US localization. Total hemoglobin concentration and oxygen saturation were measured for each breast lesion. Sensitivity, specificity, overall accuracy, positive predictive value, and negative predictive value were determined with surgical pathologic examination results as the verification standard.Of the 136 biopsied lesions, 54 were carcinomas and 82 were benign. The average total hemoglobin concentration in the malignant group was 223.3 μmol/L±55.8 (standard deviation), and the average hemoglobin concentration in the benign group was 122.5 μmol/L±80.6 (P=.005). When the maximum hemoglobin concentration of 137.8 μmol/L was used as the threshold value, the sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of DOT with US localization were 96.3%, 65.9%, 65.0%, 96.4%, and 76.5%, respectively. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of conventional US were 96.3%, 92.6%, 89.7%, 97.4%, and 93.4%, respectively. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of conventional US combined with DOT were 100%, 93.9%, 91.5%, 100%, and 96.3%, respectively.US-guided DOT combined with conventional US improves accuracy compared with DOT alone.

Persistently activated or tyrosine-phosphorylated STAT3 (pSTAT3) is found in 50% of lung adenocarcinomas. pSTAT3 is found in primary adenocarcinomas and cell lines harboring somatic-activating mutations in the tyrosine kinase domain of EGFR. Treatment of cell lines with either an EGFR inhibitor or an src kinase inhibitor had no effect on pSTAT3 levels, whereas a pan-JAK inhibitor (P6) blocked activation of STAT3 and inhibited tumorigenesis. Cell lines expressing these persistently activated mutant EGFRs also produced high IL-6 levels, and blockade of the IL-6/gp130/JAK pathway led to a decrease in pSTAT3 levels. In addition, reduction of IL-6 levels by RNA interference led to a decrease in tumorigenesis. Introduction of persistently activated EGFR into immortalized breast epithelial cells led to tumorigenesis, IL-6 expression, and STAT3 activation, all of which could be inhibited with P6 or gp130 blockade. Furthermore, inhibition of EGFR activity in multiple cell lines partially blocked transcription of IL-6 and concurrently decreased production and release of IL-6. Finally, immunohistochemical analysis revealed a positive correlation between pSTAT3 and IL-6 positivity in primary lung adenocarcinomas. Therefore, mutant EGFR could activate the gp130/JAK/STAT3 pathway by means of IL-6 upregulation in primary human lung adenocarcinomas, making this pathway a potential target for cancer treatment.

333 Background: Genetic alterations within ERCC2 correlate with extraordinary responses to neoadjuvant cisplatin-based chemotherapy and bladder-sparing ionizing radiation (IR) in muscle-invasive bladder cancer (MIBC). Two studies correlated ERCC2 mutations with pathologic response to chemotherapy and improved disease-free and bladder intact survival following trimodality therapy. We sought to characterize the biological significance of these mutations in bladder cancer cells using CRISPR/Cas9-mediated ablation of ERCC2 function. Methods: The ERCC2 T484A/M point mutation was the most common alteration (4 of 36 patients) within a prospectively collected cohort of 299 bladder cancer patients sequenced at our institution. We infected the ERCC2 wild-type KU19-19 bladder cancer cell line with a CRISPR/Cas9 lentivirus targeting residues 481-487 of ERCC2 and identified a cell clone harboring an ERCC2 in-frame deletion (M483_T484del). Following exposure to cisplatin and IR, cell viability was examined using Cell-titer Glo and clonogenic assays. Apoptosis was gauged by subG1 cell fraction measurement by flow cytometry. Results: ERCC2 mutant cells exhibited significantly increased cisplatin sensitivity compared to parental cells (IC50 0.3uM vs 2.0uM, p < 0.0001). Cisplatin treatment after 48 hours resulted in increased apoptosis in ERCC2 mutant vs parental cells (sub-G1 fraction 52% vs 16%, p = 0.01). ERCC2 mutant cells were more sensitive to combined IR (2 Gy) and cisplatin (1uM) compared to parental cells (SF2Gy (surviving fraction) 17 % vs 60%). Conclusions: ERCC2 mutations enhance cisplatin and IR sensitivity in a bladder cancer cell line model. ERCC2 alterations are likely the genetic basis for extraordinary response to cisplatin chemotherapy and IR in MIBC patients. Prospective genetic sequencing may help select ERCC2 mutant MIBC patients who are most likely to respond to chemotherapy or trimodality bladder-sparing therapy.

Mutational hotspots indicate selective pressure across a population of tumor samples and drive the dysregulation of proliferation, invasion, and apoptosis in many human tumors. We recently performed a comprehensive analysis of hotspot mutations in 11,000 retrospectively characterized primary untreated cancers, revealing widespread lineage diversity and mutational specificity. Yet, as broad-based clinical sequencing has begun to guide the routine care of patients, most clinically sequenced cancer patients present with recurrent or metastatic solid tumors. Furthermore, such tumors likely possess distinct mutational patterns driven by prior treatment exposure or treatment-associated evolution after diagnosis that are undetectable in primary untreated samples. We therefore sought to expand our analysis to incorporate such prospectively characterized active cancer patients as part of an ongoing initiative at Memorial Sloan Kettering Cancer Center. With nearly 10,000 patients profiled thus far, this growing prospective dataset with extensive clinical and treatment history is a transformative resource and the largest of its kind. Here, we combined these prospective data with retrospective studies to analyze the somatic mutational landscape of 21,000 cancer patients across 74 cancer types representing the broadest range of human malignancies characterized to date. We developed and applied a biologically and statistically principled computational model to identify hotspots mutated more frequently than would be expected in the absence of selection. This analysis uncovered hundreds of new biologically and therapeutically relevant candidate driver mutations for which targeted agents are currently being investigated in early phase trials. Indeed, we identify several hotspots in key effectors of PI3K and MAPK signaling with differential response in vitro to current investigational therapies suggesting mutant allele-specific therapeutic decisions may be warranted. In total, over half of all hotspot mutations identified were novel, including several novel hotspots in small GTPase RAC1 that are lineage specific and functionally distinct. Understanding the distinct molecular function of these mutations, and the specific mutant alleles at individual codons, is a necessary translational prerequisite for enabling precision oncology through clinical decision support for patients sequenced at the point of care. Citation Format: Matthew T. Chang, Sizhi Paul Gao, Tripti Shrestha Bhattarai, Tambudzai Shamu, Cyriac Kandoth, Saurabh Asthana, Jocelyn S. Chapman, JianJiong Gao, Nicholas D. Socci, Adam B. Olshen, David M. Hyman, Michael F. Berger, David B. Solit, Nikolaus D. Schultz, Barry S. Taylor. Identifying novel recurrent mutations reveals candidate actionable mutations. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4366.

Purpose: Novel therapeutic regimens are needed to improve the dismal outcomes of patients with anaplastic thyroid cancer (ATC). Oncolytic herpes simplex virus have shown promising activity against human ATC. We studied the application of oncolytic herpes simplex virus (G207 and NV1023) in combination with currently used chemotherapeutic drugs (paclitaxel and doxorubicin) for the treatment of ATC. Experimental Design and Results: All four agents showed dose-response cytotoxicity in vitro for the human ATC cell lines KAT4 and DRO90-1. G207, combined with paclitaxel, showed synergistic cytotoxicity. Chou-Talalay combination indices ranged from 0.56 to 0.66 for KAT4, and 0.68 to 0.74 for DRO90-1 at higher affected fractions. Paclitaxel did not enhance G207 viral entry and early gene expression or G207 viral replication. Paclitaxel combined with G207 compared with single-agent treatment or controls showed significantly increased microtubule acetylation, mitotic arrest, aberrant chromatid separation, inhibition of metaphase to anaphase progression, and apoptosis. A single i.t. injection of G207 combined with biweekly i.p. paclitaxel injections in athymic nude mice bearing KAT4 flank tumors showed significantly reduced mean tumor volume (74 ± 38 mm3) compared with G207 alone (388 ± 109 mm3), paclitaxel alone (439 ± 137 mm3), and control (520 ± 160 mm3) groups at 16 days. There was no morbidity in vivo attributable to therapy. Conclusions: Mechanisms of paclitaxel antitumoral activity, including microtubule acetylation, mitotic block, and apoptosis, were enhanced by G207, which also has direct oncolytic effects. Combination of G207 and paclitaxel therapy is synergistic in treating ATC and holds promise for patients with this fatal disease.

473 Background: Approximately 30% of patients with advanced germ cell tumor (aGCT) will progress after first-line chemotherapy. Nearly half of these patients will die of progressive GCT. We describe potentially actionable mutations in a cohort of patients with platinum-resistant aGCT through targeted sequencing. Methods: 76 patients with cisplatin-resistant (CR) disease were sequenced using the Memorial Sloan Kettering Integrated Mutation Profiling of Actionable Cancer Targets (MSK-IMPACT) assay that examines 341 cancer-related genes. Patients were categorized as CR if they met any of the following criteria: 1) incomplete response to first-line cisplatin-based chemotherapy; 2) nonteratomatous tumor progression after standard chemotherapy; 3) nonteratomatous GCT identified at postchemo surgery. We grouped all somatic mutations into core signal transduction pathways or canonical cell functions to identify potential precise targets for therapy. Results: The majority of patients had nonseminoma histology (n = 64, 84%). International Germ Cell Cancer Collaborative Group risk was good, intermediate, and poor in 34%, 13%, and 53% of patients. 17 patients died of disease. In total, 51 potentially actionable alterations were identified in 36/76 (47%) patients. In the TP53 pathway, 7 MDM2 amplifications and 4 MYCN amplifications that may sensitize to nutlin-3 inhibitors were identified. Within the receptor tyrosine kinase pathway, 3 KIT mutations, 1 KDR amplification, and 1 MET amplification were seen that may sensitize to tyrosine kinase inhibitors. Eleven KRAS mutations, 3 NRAS mutations, 3 BRAF mutations, and 2 RAC1 mutations were see among the RAS pathway with preclinical data suggesting efficacy towards respective inhibitors. Actionable targets were also among the PI3-K, WNT, and cell cycle pathways. Potential targets with chromatin modifying or tumor suppressor functions were also seen. Conclusions: We describe actionable alterations that may guide treatment selection in a significant proportion of patients with CR aGCT. Targeted sequencing of these patients may allow us to enrich future clinical trials with patients whose tumors harbor alterations in the drug target of interest.

Many mutations in cancer are of unknown functional significance. Standard methods use statistically significant recurrence of mutations in tumor samples as an indicator of functional impact. We extend such analyses into the long tail of rare mutations by considering recurrence of mutations in clusters of spatially close residues in protein structures. Analyzing 10,000 tumor exomes, we identify more than 3000 rarely mutated residues in proteins as potentially functional and experimentally validate several in RAC1 and MAP2K1. These potential driver mutations (web resources: 3dhotspots.org and cBioPortal.org) can extend the scope of genomically informed clinical trials and of personalized choice of therapy. Electronic supplementary material The online version of this article (doi:10.1186/s13073-016-0393-x) contains supplementary material, which is available to authorized users.

Introduction Signal transducer and activator of transcription 3 (Stat3) is constitutively tyrosine-phosphorylated in approximately 50% of primary breast carcinomas. A number of different mechanisms responsible for Stat3 activation, including abnormal activation of receptor tyrosine kinases, Src, and Janus kinases (Jaks), have been implicated in breast cancer. Methods We examined six breast cancer-derived cell lines expressing high or low levels of tyrosine-phosphorylated Stat3 (pStat3) as well as primary breast cancer specimens. Results Inhibition of Src or EGFR (epidermal growth factor receptor) tyrosine kinases had no effect on pStat3 levels, whereas pan-Jak inhibitor P6 resulted in complete abrogation of Stat3 phosphorylation and inhibition of growth. Jaks are required for cytokine signaling, and the glycoprotein 130 (gp130) receptor-associated Jaks are known mediators of Stat3 phosphorylation. Blockade of the gp130 receptor or sequestration of the interleukin-6 (IL-6) ligand led to a decrease of pStat3 levels. Conditioned media from those cell lines expressing high levels of pStat3 contained IL-6 and were capable of stimulating Stat3 phosphorylation. We examined IL-6 levels in primary breast tumors and found a positive correlation between pStat3 and IL-6 expression. Conclusion In summary, a principal mechanism of Stat3 activation in breast cancer is through the IL-6/gp130/Jak pathway.