Tumors Of Various Histologies Research Articles

Abstract 1209: Tumor informed circulating tumor DNA monitoring for early treatment response and survival outcomes on trastuzumab + pertuzumab

Abstract Background: Advances in cancer treatment have led to the rise of targeted therapies as practice-changing modalities, demonstrating significant efficacy in molecularly selected patients. However, depth of response and survival benefit is variable. Limitations in radiographic imaging create challenges in determining a clinical response. Circulating tumor DNA (ctDNA) is a promising minimally-invasive, predictive biomarker. Here we explore the utility of tumor-informed, on-treatment ctDNA dynamics for early response monitoring and prognostication in patients with HER2-positive tumors of various histologies receiving trastuzumab + pertuzumab on the phase II basket trial, MyPathway (NCT02091141). Methods: In this retrospective study, 58 patients were included based on availability of tissue comprehensive genomic profiling (CGP) results and baseline/on-treatment plasma. FoundationOne® Tracker was utilized to detect and quantify ctDNA, selecting 2-16 tumor-derived variants from tissue CGP and monitoring the corresponding patient’s plasma with multiplex PCR. ctDNA was assessed at baseline and Cycle 3 Day 1 (C3D1) of therapy. Correlations between ctDNA changes and objective response, progression-free survival (PFS) and overall survival (OS) were made using Kaplan Meier analyses and landmarked at C3D1. Patients ctDNA- at baseline and C3D1 were excluded. Results: Of the 58 patients, personalized ctDNA assays were successfully designed for 52 (89.7%) representing 14 unique tumor histologies. Of 52, 48 (92.3%) had ctDNA results available for baseline analysis with a median of 100.7 mean tumor molecules per mL (MTM/mL); 89.6% were ctDNA+ with a median of 119.5 MTM/mL. A total of 39 patients had both baseline and C3D1 results for ctDNA response analyses. On-treatment ctDNA decline >90% (N=10) was associated with longer survival compared to <90% decline (N=16) or any increase (N=13) in ctDNA (OS: NR, 9.4 months (mo); P= 0.007). CtDNA dynamics remained predictive in a disease specific analysis of colorectal cancer (N=18; OS: NR, 10.2 mo; P= 0.04). Similar results were seen when stratifying patients by baseline ctDNA level (above/below median MTM/mL) or HER2 (ERBB2) mutation vs amplification. ctDNA increase at C3D1 preceded radiographic progression by a median of 1.3 mo. In patients with stable disease, >90% decline in ctDNA was associated with longer OS compared to <90% decline or any increase (NR, 9.4 mo; P= 0.01). Conclusion: Tumor-informed ctDNA monitoring provides insight into early treatment response and survival outcomes in patients with diverse HER2 amplified or mutated tumors receiving HER2 targeted therapy. On-treatment ctDNA dynamics refine and can potentially detect response/progression ahead of standard of care response assessments, suggesting early ctDNA monitoring as a valuable complementary tool for real-time treatment response monitoring. Citation Format: Razelle Kurzrock, Merrida Childress, Wenshu Li, Anna Muse, Julia Malato, Yong Wang, Minetta Liu, Alexey Aleshin, Richard S. Wang, Julia Thierauf, Christopher J. Sweeney, John Hainsworth, Tania Szado, Amanda Young, Katja Schulze, David Spigel, Funda Meric-Bernstam, Charles Swanton, Howard A. Burris. Tumor informed circulating tumor DNA monitoring for early treatment response and survival outcomes on trastuzumab + pertuzumab [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 1209.

Effect of a novel expansion process on tumor-infiltrating lymphocyte (TIL) polyfunctionality, cytotoxicity, and expansion, while preserving cells in a less differentiated and more stem-like phenotype.

2542 Background: Adoptive cell therapy using autologous TIL has shown durable responses in patients with metastatic melanoma and some epithelial tumors (Chesney JITC 2022; Schoenfeld SITC 2021; O’Malley SITC 2021). Data suggest that maintaining a higher proportion of less differentiated and more stem-like TIL can associate with persistence and response in patients with metastatic melanoma (Krishna Science 2020; Rosenberg Clin Cancer Res 2011). Here, we describe a novel TIL expansion process that increases TIL expansion and preserves cells in a less-differentiated and more stem-like phenotype with enhanced functional output. Methods: Tumors of various histologies, including lung, breast, and renal cancer, were fragmented and expanded using either a standard process or a newly developed process that uses a different combination of cytokines during the pre-rapid expansion protocol (pre-REP) stage and another combination of cytokines and a pathway inhibitor during the REP stage to control T-cell activation and differentiation. The expansion potential, viability, and phenotypic and functional attributes of the final TIL products were evaluated by a variety of assays. Results: When compared with standard TIL expansion, the novel process increased yield and viability while preserving TIL in a less differentiated and more functional state, as evidenced by increased expression of the memory-associated markers CD27, CD28, CD62L, and IL-7R, with reduced expression of the activation markers CD38, CD39, and CD69, and lower levels of the inhibitory markers LAG3, TIM3, TIGIT, and TOX. Importantly, the novel process led to a pronounced increase in the tumor-homing marker CXCR3 as well as TIL polyfunctionality as evidenced by increased co-expression of IFNγ, TNFα, and IL-2 while showing an enrichment in genes associated with stem-like cells and a reduction in exhaustion-associated genes. Pseudotime trajectory analysis also demonstrated that the new expansion process maintained TIL in a less differentiated and more stem-like state. Together, these phenotypic and functional characteristics translated into increased cytotoxicity even after repeated stimulation. Conclusions: Our novel TIL expansion process improves multiple metrics that correlate with both TIL persistence and response, including enhanced polyfunctionality, reduced inhibitory receptor expression and a less differentiated and more stem-like phenotype, while increasing yield. These effects may translate into a more vigorous and less differentiated TIL infusion product with improved cytotoxicity and persistence.

Larotrectinib Treatment for Patients With TRK Fusion-Positive Salivary Gland Cancers.

Larotrectinib is a first-in-class, highly selective, and central nervous system-active tropomyosin receptor kinase (TRK) inhibitor approved for the treatment of adult and pediatric patients with TRK fusion cancer. We report the efficacy and safety of larotrectinib in patients with TRK fusion-positive salivary gland cancers. Patients with TRK fusion-positive salivary gland cancer treated with larotrectinib were identified from two clinical trials (NCT02122913 and NCT02576431). Patients received larotrectinib 100 mg twice daily (BID) except for one patient who received 150 mg BID in the phase I trial. The primary endpoint was objective response rate (ORR) as assessed by the investigator using Response Evaluation Criteria in Solid Tumors version 1.1. At the data cut-off (July 20, 2020), 24 patients with TRK fusion-positive salivary gland cancer had been treated. The most common histologies were secretory carcinoma (54%), adenocarcinoma (25%), and mucoepidermoid carcinoma (13%). All 24 patients had an ETV6-NTRK3 gene fusion. The ORR was 92% (95% confidence interval, 73-99). Best overall response was complete response in three (13%) patients, partial response in 19 (79%), and progressive disease in two (8%). The rate of progression-free survival at 24 months was 78% (median follow-up 30.9 months). Most treatment-related adverse events (AEs) were grade 1-2, and no patients discontinued treatment due to AEs. Larotrectinib demonstrated robust and durable efficacy in patients with TRK fusion-positive salivary gland tumors of various histologies, and a favorable safety profile. These findings support NTRK gene fusion testing in patients with advanced salivary gland cancers. NCT02122913 and NCT02576431.

Frequent FGFR1 hotspot alterations in driver-unknown low-grade glioma and mixed neuronal-glial tumors

PurposeLow-grade gliomas (LGG) and mixed neuronal-glial tumors (MNGT) show frequent MAPK pathway alterations. Oncogenic fibroblast growth factor receptor 1 (FGFR1) tyrosinase kinase domain has been reported in brain tumors of various histologies. We sought to determine the frequency of FGFR1 hotspot mutations N546 and K656 in driver-unknown LGG/MNGT and examined FGFR1 immunohistochemistry as a potential tool to detect those alterations.MethodsWe analyzed 476 LGG/MNGT tumors for KIAA-1549-BRAF fusion, IDH1/2, TERT promotor, NF1, H3F3A and the remaining cases for FGFR1 mutation frequency and correlated FGFR1 immunohistochemistry in 106 cases.Results368 of 476 LGG/MNGT tumors contained non-FGFR1 alterations. We identified 9 FGFR1 p.N546K and 4 FGFR1 p.K656E mutations among the 108 remaining driver-unknown samples. Five tumors were classified as dysembryoplastic neuroepithelial tumor (DNT), 4 as pilocytic astrocytoma (PA) and 3 as rosette-forming glioneuronal tumor (RGNT). FGFR1 mutations were associated with oligodendroglia-like cells, but not with age or tumor location. FGFR1 immunohistochemical expression was observed in 92 cases. FGFR1 immunoreactivity score was higher in PA and DNT compared to diffuse astrocytoma, but no correlation between FGFR1 mutation in tumors and FGFR1 expression level was observed.ConclusionFGFR1 hotspot mutations are the fifth most prevailing alteration in LGG/MNGT. Performing FGFR1 sequencing analysis in driver-unknown low-grade brain tumors could yield up to 12% FGFR1 N546/K656 mutant cases.

Abstract 2991: Mutational screening of BRCA1/2 genes in 667 spontaneous canine tumors

Abstract BRCA1 and BRCA2 (Breast cancer susceptibility gene 1 and 2) are tumor suppressor genes that maintain genomic stability by repairing damaged DNA. The proteins coded by these genes are involved in complexes that activate the repair of double strand breaks (DSBs) and initiate homologous recombination (HR). BRCA mutations are common in various forms of human cancers, most notably breast cancer, and previously described in canine tumors. Tumors in canines and humans share many characteristics, including: inter-individual and intra-tumoral heterogeneity, biological behavior, similar tumor microenvironments, and similar genomic mutations. This study interrogates naturally-occuring cancers in dogs as a tool that can add valuable information to our understanding of similar tumors in people. A total of 667 tumors of various histologies were obtained from client-owned dogs and sequenced on the FidoCure® Next-generation sequencing (NGS) panel as part of their veterinary precision medicine platform. Mutations in BRCA1 and BRCA2 were among the 5 most common genetic mutations identified. BRCA1 or BRCA2 mutations were identified in 71.8% (479/667) of tumors overall; 36.4% (n=243) BRCA1 mutations, 33.7% (n=225) BRCA2 mutations, and 1.6% (n=11) BRCA1/2 co-mutations. Germline single-nucleotide polymorphisms (SNPs) represented 56% (136/243) and 61% (138/225) of BRCA1 and BRCA2 mutations, respectively. Removing SNPs and focusing on single-nucleotide variants (SNVs), 16.1% of cases (107/667) had BRCA1 mutations, 13.0% (87/667) had BRCA2 mutations, and 1.65% (11/667) had both BRCA1 and BRCA2 mutations. Utilizing Protein Variation Effect Analyzed (PROVEAN) and Sort Intolerant From Tolerant (SIFT) bioinformatic tools to assess the functional significance of BRCA1 and BRCA2 missense variants, 69.2% and 54.8% of mutations, respectively, were predicted as pathogenic/deleterious. Interestingly, a search of the 2017 MSK IMPACT dataset reveals a pan-cancer prevalence in humans of 2.0% BRCA1 variants (216/10,945 cases) and 3.6% BRCA2 variants (399/10,945 cases). Looking at cancer histologies in dogs, BRCA1 variants were identified in 14.1% of soft tissue sarcomas (STS), 11.4% of apocrine gland anal-sac adenocarcinomas (AGASACA), 11.1% of mast cell tumors (MCT), 10.9% of osteosarcomas (OSA), and 10% of thyroid carcinomas. BRCA2 mutations were identified in 33.3% of MCTs, 32.1% of STSs, 23.8% of histiocytic sarcomas, 17.2% of OSAs, and 16.3% of AGASACAs. This analysis of BRCA1/2 mutations in dogs highlights the value of companion animals as a model for human disease to better understand the contribution of these genes in tumorigenesis and for exploring different targeted therapeutic interventions. Further evaluation of the efficacy of PARP inhibitors, either with or without chemotherapy and/or radiotherapy, in tumors with BRCA1/2 mutations in dogs may reveal information that can then be used to benefit humans with similar malignancies. Citation Format: Benjamin Lewis, Gerry Post, Garrett Harvey, Lindsay Lambert, Aubrey Miller, Rilke Van Buren, Christina Lopes, Lucas Rodrigues. Mutational screening of BRCA1/2 genes in 667 spontaneous canine tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2991.

Isotope tracing reveals glycolysis and oxidative metabolism in childhood tumors of multiple histologies

Survival among children with high-risk solid tumors remains poor. Reprogrammed metabolism promotes tumor growth and may contain therapeutic liabilities. Tumor metabolism has been assessed in adults using intra-operative 13C-glucose infusions. Pediatric tumors differ from adult cancers in their low mutational burden and derivation from embryonic tissues. Here we used 13C infusions to examine tumor metabolism in children, comparing phenotypes among tumor types and between childhood and adult cancers. Patients recruited to study NCT03686566 received an intra-operative infusion of [U-13C]glucose during tumor resection to evaluate central carbon pathways in the tumor, with concurrent metabolomics to provide a broad overview of metabolism. Differential characteristics were determined using multiple comparison tests and mixed effect analyses. We studied 23 tumors from 22 patients. All tumors analyzed by [U-13C]glucose contained labeling in glycolytic and tricarboxylic acid (TCA) cycle intermediates. Labeling in the TCA cycle indicated activity of pyruvate dehydrogenase (PDH) and pyruvate carboxylase (PC), with PDH predominating. Neuroblastomas had high lactate labeling relative to other childhood cancers and lung cancer, and were distinguished by abundant tyrosine catabolites consistent with catecholamine synthesis. Intra-operative [U13C]glucose infusions are safe and informative in pediatric cancer. Tumors of various histologies use glycolysis and oxidative metabolism, with subtype-selective differences evident from this small cohort. Expanding this cohort may uncover predictive biomarkers and therapeutic targets from tumor metabolism. N.C.I grants to P.L. (R21CA220090-01A1) and R.J.D. (R35CA22044901); H.H.M.I. funding to R.J.D.; Children's Clinical Research Advisory Committee funding to K.J.

Activity of larotrectinib in TRK fusion cancer patients with brain metastases or primary central nervous system tumors.

2006 Background: TRK fusions are oncogenic drivers of a variety of cancers, many of which can involve the central nervous system (CNS). Larotrectinib is an FDA-approved selective TRK inhibitor for the treatment of TRK fusion cancer (Drilon et al, NEJM 2018). While larotrectinib has been shown to cross the blood–brain barrier (Ziegler et al, Br J Cancer 2018), its clinical activity in a series of TRK fusion cancers with primary or metastatic intracranial disease has not been described. Methods: Patients (pts) with non-primary CNS solid tumors with brain metastases, or primary CNS tumors harboring a TRK fusion treated with larotrectinib in 2 clinical trials (NCT02637687, NCT02576431) were identified. Larotrectinib was administered until disease progression (PD), withdrawal, or unacceptable toxicity. Disease status was investigator-assessed (RANO and RECIST). Data cutoff: July 30, 2018. Results: 14 pts were identified: 5 non-primary CNS solid tumors (3 lung cancer, 2 thyroid cancer; fusion type: 2 ETV6-NTRK3, 2 SQSTM1-NTRK3, 1 EPS15-NTRK1; age range 25–79 y) and 9 primary CNS tumors (3 glioma, 2 glioblastoma, 1 astrocytoma, 3 NOS; fusion type: 3 BCR-NTRK2, 2 KANK-NTRK2, 1 each of AFAP1-NTRK1, AGTPBP1-NTRK2, ETV6-NTRK3, SPECC1L-NTRK2; age range 2–79 y). In the 5 pts with non-primary CNS tumors, the best objective response to therapy was PR in 3 (60%, 1 pending confirmation), SD in 1 (20%), and not evaluable (NE) in 1 (20%). Duration of response ranged from 9+ to 13 mo. In the 9 pts with primary CNS tumors, disease control was achieved in all evaluable pts (primary PD not observed; 1 pt required dose increase). The best objective response to therapy was PR in 1 (11%; pending confirmation, −55% tumor shrinkage, ongoing at 3.7 mo), SD in 7 (78%; tumor shrinkage range −1% to −24% for pts with measurable disease, 5 had SD > 4 mo), and NE in 1 (11%). Duration of treatment ranged from 2.8–9.2+ mo. Conclusions: Larotrectinib is active in pts with TRK fusion cancers with intracranial disease. Confirmed responses and durable disease control were seen in metastatic disease and primary CNS tumors of various histologies. These results further support expanded testing for TRK fusions across all cancers, including primary CNS tumors. Clinical trial information: NCT02637687 and NCT02576431.

Abstract NG05: TP53-mediated human cancer susceptibility is defined by epigenetic dysregulation of microRNA-34A

Abstract NG05: TP53-mediated human cancer susceptibility is defined by epigenetic dysregulation of microRNA-34A

Inhibition of the fibroblast growth factor receptor (FGFR) pathway: the current landscape and barriers to clinical application.

The fibroblast growth factor/fibroblast growth factor receptor (FGF/FGFR) is a tyrosine kinase signaling pathway that has a fundamental role in many biologic processes including embryonic development, tissue regeneration, and angiogenesis. Increasing evidence indicates that this pathway plays a critical role in oncogenesis via gene amplification, activating mutations, or translocation in tumors of various histologies. With multiplex sequencing technology, the detection of FGFR aberrations has become more common and is tied to cancer cell proliferation, resistance to anticancer therapies, and neoangiogenesis. Inhibition of FGFR signaling appears promising in preclinical studies, suggesting a pathway of clinical interest in the development of targeted therapy. Phase I trials have demonstrated a manageable toxicity profile. Currently, there are multiple FGFR inhibitors under study with many non-selective (multi-kinase) inhibitors demonstrating limited clinical responses. As we progress from the first generation of non-selective drugs to the second generation of selective FGFR inhibitors, it is clear that FGFR aberrations do not behave uniformly across cancer types; thus, a deeper understanding of biomarker strategies is undoubtedly warranted. This review aims to consolidate data from recent clinical trials with a focus on selective FGFR inhibitors. As Phase II clinical trials emerge, concentration on patient selection as it pertains to predicting response to therapy, feasible methods for overcoming toxicity, and the likelihood of combination therapies should be utilized. We will also discuss qualities that may be desirable in future generations of FGFR inhibitors, with the hope that overcoming these current barriers will expedite the availability of this novel class of medications.

Operating Procedures of the Electrochemotherapy for Treatment of Tumor in Dogs and Cats.

Electrochemotherapy (ECT) is a local approach which is used for treating solid tumors of different histologies. Its mechanism is based on cell membrane permeabilization by means of "electroporation". To achieve the "electroporation" of the cells, electric pulses are generated by a generator and delivered to the target tissue by the use of electrodes. Electroporation is a physical method which is used to introduce molecules, like cytostatic drugs, into the cells that could not pass the cell membrane on their own. In electrochemotherapy, currently, cisplatin and bleomycin are clinically used. Electrochemotherapy antitumor effectiveness is high, for example up to 100% complete response of canine mast cell tumors smaller than 2 cm3 was achieved. Additionally, electrochemotherapy can be used for the treatment of inoperable tumors. One of the important characteristics of electrochemotherapy is that it can be effective as a one-time treatment only. However, in the case of failure or partial tumor response it can be repeated several times with equal or improved effectiveness. Electrochemotherapy is already a standard treatment for cutaneous and subcutaneous tumors of various histologies in human and veterinary oncology. Furthermore, several clinical studies exploiting electrochemotherapy for deep-seated tumors are on-going.

Operating Procedures of the Electrochemotherapy for Treatment of Tumor in Dogs and Cats

Electrochemotherapy (ECT) is a local approach which is used for treating solid tumors of different histologies. Its mechanism is based on cell membrane permeabilization by means of "electroporation". To achieve the "electroporation" of the cells, electric pulses are generated by a generator and delivered to the target tissue by the use of electrodes. Electroporation is a physical method which is used to introduce molecules, like cytostatic drugs, into the cells that could not pass the cell membrane on their own. In electrochemotherapy, currently, cisplatin and bleomycin are clinically used. Electrochemotherapy antitumor effectiveness is high, for example up to 100% complete response of canine mast cell tumors smaller than 2 cm3 was achieved. Additionally, electrochemotherapy can be used for the treatment of inoperable tumors. One of the important characteristics of electrochemotherapy is that it can be effective as a one-time treatment only. However, in the case of failure or partial tumor response it can be repeated several times with equal or improved effectiveness. Electrochemotherapy is already a standard treatment for cutaneous and subcutaneous tumors of various histologies in human and veterinary oncology. Furthermore, several clinical studies exploiting electrochemotherapy for deep-seated tumors are on-going.

Abstract A104: Eradication of large solid tumors in immunocompetent mice using dual specific CAR T cells and vaccination

Abstract While adoptive cell transfer (ACT) using chimeric antigen receptor-expressing (CAR) T cells has led to remarkable complete responses in leukemia, complete responses of solid tumors in patients are few. Similarly, previous investigations in mice have demonstrated clearance of large burdens of disseminated cancer using CAR T cells, but large solid tumors (>1 cm2) have not responded fully. Here we report the generation of transgenic mice containing dual specific CAR T cells with specificity for Her2 and the melanoma-associated antigen pMEL (gp100), designated CARaMEL mice. In response to Her2-positive cancer cells, T cells from CARaMEL mice could secrete cytokines and engage in cytolysis mediated by an anti-Her2 CAR. Through their endogenous TCR, CARaMEL T cells could proliferate extensively in response to gp100. We demonstrate the ability of CARaMEL T cells in ACT incorporating vaccination (ACTIV) therapy to induce eradication of large tumors of various histologies, including orthotopic breast tumors, subcutaneous sarcoma and colon carcinoma liver tumors. Tumor models were performed in immunocompetent mice expressing human Her2 in normal brain and breast tissue. Effective ACTIV therapy included a lymphodepleting preparative regimen, ACT, high-dose IL-2 and recombinant vaccinia virus expressing gp100. ACTIV therapy was associated with expansion of dual-specific T cells and extensive tumor infiltration by CARaMEL T cells. Infiltration of CARaMEL T cells was also observed in normal tissues including brain. Long term surviving mice were totally resistant to rechallenge with Her2-expressing tumor cells, and partially resistant to Her2-negative tumor cells. We anticipate studies currently underway to provide mechanistic insight into the antitumor activity of ACTIV therapy. Citation Format: Clare Y. Slaney, Jennifer A. Westwood, Paul A. Beavis, Phillip K. Darcy, Michael H. Kershaw. Eradication of large solid tumors in immunocompetent mice using dual specific CAR T cells and vaccination. [abstract]. In: Proceedings of the CRI-CIMT-EATI-AACR Inaugural International Cancer Immunotherapy Conference: Translating Science into Survival; September 16-19, 2015; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2016;4(1 Suppl):Abstract nr A104.

TU‐A‐WAB‐01: Characterization of Vascular and Proliferative Flare in Anti‐Angiogenic Therapy Using FLT PET/CT and Circulating VEGF

Purpose: Previous studies observed significant rebound of tumor proliferation and vascularization following cessation of anti‐angiogenic therapy. In this study we characterize this phenomenon in a novel anti‐angiogenic agent, using both [18‐F]FLT PET/CT and circulating VEGF. Methods: Seventeen patients with solid tumors of various histologies were treated for two weeks with Axitinib, a molecularly targeted anti‐proliferative and anti‐angiogenic agent, 5mg twice daily, followed by a one‐week treatment break. Dynamic FLT PET scans were acquired at peak drug concentration (day 12–14), and washout (day 20–21). Vasculature status was quantified using a two‐compartment kinetic model (blood volume, Vb; blood‐to‐tissue transfer constant, K1). Proliferation was quantified using both kinetic analysis (net uptake rate, Ki) and SUV‐based metrics (SUVmean, SUVmax, SUVpeak, SUVtotal). Relative change in each of these metrics during washout was assessed. Blood samples obtained pre‐treatment and at each imaging time point were analyzed for the pro‐angiogenic factor VEGF (vascular endothelial growth factor). The change in VEGF during therapy was also assessed. Results: Seven of seventeen patients showed unambiguous proliferative flare, with all four SUV metrics increasing >20% during washout. Median increases of 30% SUVmean, 50% SUVmax, 60% SUVpeak, 70% SUVtotal, and 75% Ki were observed in these patients. Increase in vascular parameters were also observed in these patients (medians 30% Vb, 80% K1). Vascular and proliferative flare were correlated across all seventeen patients (ΔSUVpeak vs. ΔK1, R = 0.59). A highly significant increase in circulating VEGF (p<0.001) occurs during the treatment period, followed by a highly significant drop (p<0.001) during the withdrawal period, to a level indistinguishable from baseline (p=0.9).Conclusion: Substantial proliferative and vascular flare were observed in many patients during Axitinib withdrawal. These phenomena were correlated, suggesting Axitinib withdrawal may open a window for effective combination therapy. Axitinib treatment strongly impacts VEGF expression levels, suggesting it successfully targets the VEGF receptor. Research funded in part by the U.W. Radiological Sciences Training Grant: 5T32CA009206‐34. Research funded in part by Pfizer.

Immune targeting of fibroblast activation protein triggers recognition of multipotent bone marrow stromal cells and cachexia

Fibroblast activation protein (FAP) is a candidate universal target antigen because it has been reported to be selectively expressed in nearly all solid tumors by a subset of immunosuppressive tumor stromal fibroblasts. We verified that 18/18 human tumors of various histologies contained pronounced stromal elements staining strongly for FAP, and hypothesized that targeting tumor stroma with FAP-reactive T cells would inhibit tumor growth in cancer-bearing hosts. T cells genetically engineered with FAP-reactive chimeric antigen receptors (CARs) specifically degranulated and produced effector cytokines upon stimulation with FAP or FAP-expressing cell lines. However, adoptive transfer of FAP-reactive T cells into mice bearing a variety of subcutaneous tumors mediated limited antitumor effects and induced significant cachexia and lethal bone toxicities in two mouse strains. We found that FAP was robustly expressed on PDGFR-α(+), Sca-1(+) multipotent bone marrow stromal cells (BMSCs) in mice, as well as on well-characterized, clinical-grade multipotent human BMSCs. Accordingly, both mouse and human multipotent BMSCs were recognized by FAP-reactive T cells. The lethal bone toxicity and cachexia observed after cell-based immunotherapy targeting FAP cautions against its use as a universal target. Moreover, the expression of FAP by multipotent BMSCs may point toward the cellular origins of tumor stromal fibroblasts.

De novoInduction of a Cancer/Testis Antigen by 5-Aza-2′-Deoxycytidine Augments Adoptive Immunotherapy in a Murine Tumor Model

Recent studies suggest that immunotherapy targeting specific tumor-associated antigens (TAAs) may be beneficial in cancer patients. However, most of these TAAs are tumor type specific and heterogeneous among patients, thus limiting their applications. Here, we describe the de novo induction of a cancer/testis antigen (CTA) for immunotherapy of tumors of various histologies. The murine CTA P1A, normally expressed only in a few tumor lines, could be induced de novo in all P1A-negative cancer lines of eight histologic origins in vitro and in various murine xenografts by systemic administration of 5-aza-2'-deoxycytidine. The induction of P1A expression correlated strongly with demethylation of the CpG island in the promoter region of this gene. The induced antigen was processed and presented properly for recognition by H-2L(d)-restricted P1A-specific CTLs. The combination of a demethylating agent and adoptive transfer of P1A-specific CTL effectively treated lung metastases in syngeneic mice challenged with P1A-negative 4T1 mammary carcinoma cells. These data show a novel strategy of combined chemoimmunotherapy of cancer targeting a CTA induced de novo in a broad range of tumor histologies, and support further evaluation of chromatin-remodeling agents for human cancer therapy.

EVALUATION AND MANAGEMENT OF RENAL TUMORS IN THE BIRT-HOGG-DUBÉ SYNDROME

Herein we describe the evaluation and management of renal tumors in Birt-Hogg-Dubé (BHD), an autosomal dominant disorder predisposing to cutaneous fibrofolliculomas, pulmonary cysts, spontaneous pneumothorax and renal tumors. A total of 124 affected individuals underwent comprehensive clinical evaluation, including body computerized tomography, to determine cutaneous, pulmonary and renal manifestations of BHD. Of these individuals 14 had their renal tumors managed at our institution. Of the 124 BHD affected individuals 34 (27%) had renal tumors of various histologies, most commonly hybrid oncocytic tumor and chromophobe renal carcinoma. Average age at renal tumor detection was 50.4 years and multiple tumors were found in a majority of patients. Some patients with renal tumors were identified that did not have the characteristic cutaneous hallmarks of BHD. In 4 of the 14 patients treated at our institution small (less than 3 cm) renal tumors were observed, while 10 others underwent a total of 12 renal procedures, including 4 radical and 8 partial nephrectomies. At a median of 38 months of followup 5 of these 10 patients remained free of disease, 3 had small renal tumors and 2 died of metastatic renal cancer. Patients with BHD are at risk for multiple renal tumors that are often malignant and can metastasize. Individuals at risk or affected by BHD should be radiographically screened for renal tumors at periodic intervals and they are best treated with nephron sparing surgical approaches. Genetic testing for this syndrome is now available.

HLA-G and MIC expression in tumors and their role in anti-tumor immunity

Non-classical MHC class Ib molecules have attracted growing interest in recent years, especially because they interact with non-T-cell inhibitory or triggering receptors expressed on natural killer (NK) and T cells, suggesting that they have a role in immune recognition. Abnormalities in MHC class Ib expression are frequently found in human tumors of various histologies and might be associated with poor clinical outcome despite the local accumulation of immune competent cells. Available data suggest that the balance between activating and suppressing signals significantly influences the efficacy of the immune response and consequently of tumor progression.

Mass energy‐absorption coefficients and mass collision stopping powers for electrons in tumors of various histologies

The mass energy‐absorption coefficients and electron mass collision stopping powers have been calculated for tumors of various histologies. Eleven excised or biopsied tumor specimens were considered, including samples from two squamous cell lung carcinomas, two sarcomas, three adenoid cystic carcinomas, two melanomas and two rectal carcinomas. The hydrogen, carbon, nitrogen and oxygen composition of the tumor samples was determined. Photon mass energy‐absorption data in the energy range 1 keV to 20 MeV have been calculated using elemental mass energy‐absorption coefficients previously calculated by Hubbell and Seltzer. Electron mass collision stopping powers for energies between 10 keV and 60 MeV were calculated from the values for water using the data and methodology described in ICRU Report #37. The ratio of the average mass energy‐absorption coefficient of the tumor samples to the coefficient of water was found to be 0.99 across most of the energies of clinical interest (>100 keV) except for photon energies of 5 MeV and above for which the ratio dropped to 0.98. The ratio of the average electron mass collision stopping power of the tumor specimens to that of water was 0.99 for all energies.

The clonogenic assay with human tumor xenografts: Evaluation, predictive value and application for drug screening

The feasibility, evaluation and predictive value of the colony-forming assay with human tumor xenografts for screening anticancer drugs have been studied. Using human tumors grown in serial passage in nude mice, adequate colony formation was observed in 215 of 251 (86%) different solid human tumors of various histologies. Based on in vitro growth characteristics, a quality-controlled assay protocol was developed. With the proposed criteria for standardized evaluation of individual experiments a substantial increase in assay reliability was achieved. The five clinically established agents, cisplatin, doxorubicin, etoposide, mitomycin-C and vindesine, were studied for anticancer activity in the clonogenic assay. Drugs were applied over a wide dose range by continuous exposure, yielding clear dose-response effects with coefficients of correlation between r = 0.946 and 0.995. Relevant dose levels predicting correctly for the clinical efficacy of the agents were determined by comparison of in vitro anticancer activity to in vitro toxicity on human bone marrow as follows: cisplatin 0.1 micrograms/ml, doxorubicin 0.01 micrograms/ml, etoposide 0.1 micrograms/ml, mitomycin-C 0.005 micrograms/ml, vindesine 0.01 micrograms/ml. At these concentrations, clinically sensitive tumor types showed inhibition of colony formation in 99 of 240 cases (41%), whereas 11% (19/176) of clinically resistant tumors were responsive. The relevant dose levels used equal between 0.3% and 4.0% of the achievable peak plasma concentrations in man. The predictive value of the clonogenic assay was determined by treatment of the same tumors in vitro and in vivo in tumor-bearing nude mice. In 174/220 comparisons (79%), in vitro data predicted correctly for the in vivo sensitivity of the xenografted malignancies.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood supply of pulmonary metastases

There is a widely held belief that metastases to the lung (like primary lung tumors) are supplied by the bronchial arteries and that pulmonary neovascularization does not occur. In 17 human lungs, we have demonstrated, both in vitro and in vivo, pulmonary circulation to metastases. We have confirmed this in a series of animal studies in which we implanted tumors of various histologies into rats' tails and induced metastases from these tumors into the lungs. Forty-eight percent of these metastases had an entirely pulmonary circulation, 36% a primarily pulmonary circulation with a small bronchial component, and only 16% of metastases, located in the central one third of the lung, had an exclusively bronchial circulation. We have now shown that these supplying pulmonary vessels to metastases can be clearly demonstrated on thin-section computed tomography of the lungs. This may prove to be a helpful, noninterventional diagnostic criterion for distinguishing a primary from a metastatic lesion.