Tumor Burden Response Research Articles

Objective response after immune checkpoint inhibitors in a chemotherapy-refractory pMMR/MSS metastatic rectal cancer patient primed with experimental AlloStim® immunotherapy

BackgroundImmune Checkpoint Inhibitor (ICI) immunotherapy is most effective in immune effector cell infiltrated ‘hot’ tumor lesions, such as occurs in deficient mismatch repair, microsatellite instability high (dMMR/MSI-H) colorectal cancer (CRC). However, most all metastatic CRC tumors are mismatch repair proficient/microsatellite stable (pMMR/MSS) ‘cold’ lesions, without significant immune cell infiltration, and are unresponsive to ICI. AlloStim®, is an experimental, allogeneic immunomodulatory cell therapy designed to convert ‘cold’ metastatic tumor lesions to ‘hot’ inflamed lesions. After AlloStim® immunotherapy, this cold to hot inflammatory mechanism can make it difficult to distinguish between pseudoprogression and actual progression on restaging CT scans, as inflamed metastatic lesions can appear larger and occult disease can appear as new small lesions.MethodsTo explore whether radiological progression after AlloStim® immunotherapy is due to immune-flare or disease progression, we administered a short course of a combination ICI therapy to a pMMR/MSS chemotherapy-refractory metastatic colorectal cancer patient enrolled in the StimVax Phase IIb clinical study that presented with radiological progression after AlloStim® immunotherapy. Our rationale was that an accelerated response to ICI should occur if the lesions were inflamed, while if the enlarged lesions were due to disease progression there would not be a response.ResultsHere we report a rapid, significant reduction in tumor burden in response to ICI administration in an AlloStim® primed pMMR/MSS mCRC patient with retroperitoneal and lung metastases.ConclusionThis rare objective response to ICIs in a pMMR/MSS mCRC patient supports further evaluation of the combination of AlloStim® with ICI immunotherapy in MSS mCRC and other cold or ICI refractory tumors.Trial registrationNational Library of Medicine (NLM) at the National Institutes of Health (NIH). Registered 22 June 2020, https://clinicaltrials.gov/study/NCT04444622.

Evaluation of Tumor Burden Response to Single-cycle of Lu-177 PSMA Treatment with Whole Body Scintigraphic Planar Images in Prostate Cancer Patients

The aim of this study; evaluation of treatment response and survival with post-therapy images in patients who received one cycle of Lu-177 PSMA I&T treatment.

Attenuation of Tumor Burden in Response to Rucaparib in Lung Adenocarcinoma: The Contribution of Oxidative Stress, Apoptosis, and DNA Damage.

In cancer, overactivation of poly (ADPribose) polymerases (PARP) plays a relevant role in DNA repair. We hypothesized that treatment with the PARP inhibitor rucaparib may reduce tumor burden via several biological mechanisms (apoptosis and oxidative stress) in mice. In lung tumors (LP07 lung adenocarcinoma) of mice treated/non-treated (control animals) with PARP inhibitor (rucaparib,150 mg/kg body weight/24 h for 20 day), PARP activity and expression, DNA damage, apoptotic nuclei, cell proliferation, and redox balance were measured using immunoblotting and immunohistochemistry. In lung tumors of rucaparib-treated mice compared to non-treated animals, tumor burden, PARP activity, and cell proliferation decreased, while DNA damage, TUNEL-positive nuclei, protein oxidation, and superoxide dismutase content (SOD)2 increased. In this experiment on lung adenocarcinoma, the pharmacological PARP inhibitor rucaparib elicited a significant improvement in tumor size, probably through a reduction in cell proliferation as a result of a rise in DNA damage and apoptosis. Oxidative stress and SOD2 also increased in response to treatment with rucaparib within the tumor cells of the treated mice. These results put the line forward to the contribution of PARP inhibitors to reduced tumor burden in lung adenocarcinoma. The potential implications of these findings should be tested in clinical settings of patients with lung tumors.

Abstract B006: Development of a NF1-MPNST-PDX liquid biopsy model using whole-genome sequencing and quantitative PCR of mouse-derived cell-free DNA

Abstract Background: Malignant Peripheral Nerve Sheath Tumors (MPNST) are aggressive, NF1-associated soft tissue sarcomas with a dismal 40% 5-year survival rate, high rates of disease relapse and metastasis, and limited treatment options. Our lab has generated a collection of patient-derived xenograft (PDX) models, which recapitulate the variety of genetic changes that occur in human NF1-MPNST. Longitudinal analysis of PDX tumor burden in preclinical studies is currently limited to imprecise tumor measurement or expensive and time-consuming imaging modalities such as MRI. These methods of analysis fail to allow for the early detection of tumor formation, the assessment of treatment-response dynamics, the formation of resistant subclones, or the detection of molecular residual disease. Liquid biopsies using plasma-derived cell-free DNA (cfDNA) have been successful in addressing these challenges in the context of multiple solid tumor types including MPNST by our group previously (Szymanski et al. 2021). However, liquid biopsy of cfDNA in the context murine model systems is quite limited, primarily due the challenge of collecting sufficient plasma for analysis. We hypothesize that we can detect and longitudinally track tumor burden in response to treatment using human-tumor-specific quantitative PCR (qPCR) and whole-genome sequencing of sequentially collected PDX-bearing murine plasma to develop a NF1-MPNST-PDX liquid biopsy model. Methods: To address this challenge, we sequentially collected ≈50 µL of murine plasma weekly from two independent groups of NF1-MPNST-PDX-bearing mice and corresponding PDX-free controls for up to six weeks. The first group consisted of six PDX-bearing mice who underwent whole-genome sequence of murine-derived plasma cfDNA and paired PDX tissue. The second group consisted of fifteen NF1-MPNST-PDX-bearing mice and five PDX-free controls; plasma cfDNA samples collected from this group underwent human-specific LINE-1 qPCR, which should only detect human DNA derived from implanted PDX and allow for longitudinal tracking of tumor burden. Results: We serially collected ≈50 µL of plasma weekly from NF1-MPNST-PDX mice with no obvious impact on mouse survival or weight. Mean total cfDNA yield from the terminally collected samples was 1.12 ± 1.02 ng per uL plasma (n=21) for PDX-bearing animals with cfDNA fragments canonically appearing between 70 and 450 bps as determined by electropherogram. Whole-genome sequencing of murine plasma cfDNA revealed broad genomic aneuploidy detectable in NF1-MPNST-PDX plasma which corresponded to alterations present in PDX tissue, including MPNST-specific chromosome 8q gain, corresponding with our earlier findings (Dehner et al. 2021). Human-specific LINE-1 qPCR showed specific enrichment of tumor-derived LINE-1 in NF1-MPNST-PDX-bearing mice compared to PDX-free mice which showed no human LINE-1 enrichment. Conclusion: Our data suggest that PDX plasma cfDNA may be an informative biomarker that can be non-invasively collected and used to track tumor burden in NF1-MPNST-PDX models. Citation Format: Paul A. Jones, Wenjia Feng, Xiaochun Zhang, Peter K. Harris, Taylor Sundby, Jeffrey J. Szymanski, Divya Srihari, Faridi Qaium, Jack F. Shern, Aadel A. Chaudhuri, Angela C. Hirbe. Development of a NF1-MPNST-PDX liquid biopsy model using whole-genome sequencing and quantitative PCR of mouse-derived cell-free DNA [abstract]. In: Proceedings of the AACR Special Conference: Sarcomas; 2022 May 9-12; Montreal, QC, Canada. Philadelphia (PA): AACR; Clin Cancer Res 2022;28(18_Suppl):Abstract nr B006.

Plasma Cell-free DNA chromosomal instability score as early predictor to monitor tumor burden in response to therapeutic in multiple myeloma patients

Multiple myeloma (MM) is a plasma cell malignancy characterized by chromosomal instabilities (CIN), including complex cytogenetic and molecular abnormalities. Cell-free DNA (cfDNA) offers the potential for minimally invasive genome-wide profiling of tumor alterations in monitoring tumor burden without tumor biopsy and may be associated with cancer precision medicine and patient prognosis. The better response is associated with improved overall survival (OS) in MM, but data on early response at treatment two cycle to predictor the prognosis are limited.

Abstract 5027: Sequencing the tumor microenvironment and myeloid derived suppressor cells to understand response to immunotherapy in primary HER2 positive breast cancer

Abstract The purpose of this study is to identify how the epigenetic modulator entinostat reprograms myeloid derived suppressor cells (MDSCs) to prime the tumor microenvironment (TME) and modulate immunotherapy response. Early trials investigating single agent ICIs, anti-CTLA-4 and anti-PD-1/PD-L1, resulted in overall response rates of 5-20% in patients with metastatic HER2 positive breast cancer but little is understood about use of these therapies in patients with early stage/ primary disease. Suboptimal and inconsistent immune responsiveness is likely the result of multiple suppressive signals within the TME that provide a formidable barrier to T cell infiltration leading to an opportunity for TME modulation to potentially improve response. We and others have shown that immunosuppressive factors can be overcome by adding the class 1 histone deacetylase inhibitor, entinostat, to ICIs to reprogram MDSCs and upregulate T cell attracting signals within the TME. We hypothesize that gene expression signatures of reprogrammed MDSCs are predictive of response with subsequent immunotherapy treatment. To test this hypothesis, we used the neu-N syngeneic mouse model of HER2 positive breast cancer. We investigated differences in survival and tumor burden in response to combinations of entinostat with anti-PD-1 and anti-CTLA-4. Having previously identified MDSCs as important targets of entinostat that modulate response to ICIs, we used methods we developed to study MDSC function. Given the broad effects of entinostat on global gene expression including that of MDSCs, we used single cell RNA-seq (scRNA-seq) on primary tumors and isolated intratumoral MDSCs to determine what is driving changes in MDSC function in primary tumors. We plan to use data obtained from scRNA-seq to develop signatures of response and identify changes in responders vs. non-responders to help develop biomarkers of response in primary disease. Our results thus far show that treatment with entinostat + ICIs improves survival, and decreases tumor burden in primary tumors. Ex-vivo studies of MDSCs demonstrate changes in immunosuppressive capabilities of MDSCs and show differences in infiltration and function of granulocytic vs. monocytic MDSCs. We expect that evaluation of the ongoing sequencing data will identify more specific immune targets within primary TME and help us understand the importance of targeting MDSCs in early disease. We predict this work will identify additional candidate targets for therapeutic testing to convert breast cancers into immune responsive tumors, and that this will facilitate improved response to ICIs that will ultimately translate into improved survival of patients with breast cancer. Citation Format: Evanthia T. Roussos Torres, Christine Rafie, Emily Davis, Luciane T. Kagohara, Elana J. Fertig, Elizabeth M. Jaffee. Sequencing the tumor microenvironment and myeloid derived suppressor cells to understand response to immunotherapy in primary HER2 positive breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 5027.

Plasma cell-free DNA chromosomal instability score as early predictor to monitor tumor burden in response to therapeutic in multiple myeloma patients.

8036 Background: Multiple myeloma (MM) is a plasma cell malignancy characterized by chromosomal instabilities (CIN). Here we investigate the potential of cell-free DNA CIN as non-invasive biomarker to predict early response for MM treatments. Methods: In this prospective study, we recruited 11 relapsed/refractory (RRMM) and 19 newly diagnosed (NDMM) patients at Changzheng Hospital. Plasma samples were collected after finished two cycles or one month (RRMM) of therapy, with matched ones before the current regimen. cfDNA was extracted, followed by CIN analyses by using a customized bioinformatics workflow, ultrasensitive chromosomal aneuploidy detector (UCAD). Criteria for response and progression were according to the IMWG (Durie BG et al. 2006). Results: 7 (23%) patients (5 RRMM and 2 NDMM) showed high cfDNA CIN regard as strong positive after two cycles of treatment. Plasma cfDNA CIN profiling found complex clonal evolution compared two cycles to baseline. Multiple genomic regions, including chr7, 17p (TP53), 12q and 3p, were involved in clonal evolution. The degree of cfDNA CIN correlated with myeloma stage and overall survival. Remarkably, of the 5 heavily treated RRMM patients and 1 primary refractory newly diagnosed patient, 3 died within 60 days after the last time of cfDNA detection. Nine patients (30%) of patients showed positive cfDNA CIN after two cycles of treatment, which response rate was 11% (n=1) with SD, 33% (n=3) with MR, and 56% with PR, respectively. Fourteen patients with 5 RRMM and 9 NDMM were detected marginal or negative cfDNA CIN after two cycle’s treatment. The overall response rate in 14 patients was 100%, including 14.3% with a complete response, 14.3% with a very good partial response (VGPR), 57.1% with a PR, and 14.3% with a MR. Of these patients, 3 RRMM who received with more than six lines of therapy, showed positive cfDNA CIN. Subsequently, these three heavily treated RRMM patients have chance to enroll the chimeric antigen receptor T-Cell immunotherapy (CAR-T) therapy (enrolled NCT03093168). Surprisedly, all of them benefit from the CAR-T therapy to improve responses dramatically, meanwhile, the dynamics of total cfDNA concentration correlated with tumor burden to negative. Conclusions: We provide evidence that cfDNA level correlates with tumor burden and response rate in MM. For heavily pre-treated advanced RRMM patients with cfDNA CIN positive were benefit from the CAR-T therapy. Therefore, serial plasma cfDNA analysis is a robust and sensitive tool for monitoring response to therapy.

Monitoring Tumor Burden in Response to FOLFIRINOX Chemotherapy Via Profiling Circulating Cell-Free DNA in Pancreatic Cancer.

We aimed to explore the application of circulating cell-free DNA (cfDNA) profiling in monitoring tumor burden in patients with pancreatic ductal adenocarcinoma (PDAC). Thirty-eight patients with advanced PDAC receiving first-line FOLFIRINOX chemotherapy were prospectively enrolled. Next-generation sequencing for a panel of 560 genes covering a wide range of cancer-related loci was performed to profile cfDNA. In total, 25 patients (65.8%) had at least one common driver gene alterations (KRAS, TP53, SMAD4, CDKN2A) detected within cfDNA. In contrast, no above tumor-related recurrent mutations were found in plasma from 13 healthy individuals. Concordant alterations in plasma cfDNA and tumor tissue DNA was confirmed in two of three patients with available tissues. Further analysis showed that mutant allele fraction (MAF) for altered loci in cfDNA correlated with tumor stage, metastatic burden, and overall survival. Serial blood samples were collected from 17 patients after chemotherapy. We found that allele fraction for specific altered loci declined in chemotherapy-responding subjects. For cases who were resistant to this therapeutic regimen, increased ctDNA MAF was observed at the time of disease progression. Meanwhile, the dynamics of total cfDNA concentration correlated with tumor burden following chemotherapy. Collectively, we provide evidence that pretreatment ctDNA level correlates with tumor burden in PDAC, and serial cfDNA analysis is a robust tool for monitoring cancer response to chemotherapy.

Finite Element Analysis of the Mouse Distal Femur with Tumor Burden in Response to Knee Loading.

Breast cancer-associated bone metastasis induces bone loss, followed by an increased risk of bone fracture. To develop a strategy for preventing tumor growth and protecting bone, an understanding of the mechanical properties of bone under tumor burden is indispensable. Using a mouse model of mammary tumor, we conducted finite element analysis (FEA) of two bone samples from the distal femur. One sample was from a placebo-treated mouse, and the other was from a mouse treated with the investigational drug candidate, PD407824, an inhibitor of checkpoint kinases. Mechanical testing and microCT images revealed that bone strength is improved by administration of PD407824. In response to loading to the knee, FEA predicted that the peaks of von Mises stress, an indicator of fracture yielding, as well as the third principal compressive stress, were higher in the placebo-treated femur than the drug-treated femur. Higher peak stresses in trabecular segments were observed in the lateral condyle, a critical region for integrity of the knee joint. Collectively, this FE study supports the notion that mechanical weakening of the femur was observed in the tumor-invaded trabecular bone, and chemical agents such as PD407824 may potentially assist in preventing bone loss and bone fracture.

Stereotactic body radiation therapy for liver oligo-recurrence and oligo-progression from various tumors.

PurposeTo evaluate the outcomes of stereotactic body radiation therapy (SBRT) for patients with liver oligo-recurrence and oligo-progression from various primary tumors. Materials and MethodsBetween 2002 and 2013, 72 patients with liver oligo-recurrence (oligo-metastasis with a controlled primary tumor) and oligo-progression (contradictory progression of a few sites of disease despite an overall tumor burden response to therapy) underwent SBRT. Of these, 9 and 8 patients with uncontrollable distant metastases and patients immediate loss to follow-up, respectively, were excluded. The total planning target volume was used to select the SBRT dose (median, 48 Gy; range, 30 to 60 Gy, 3–4 fractions). Toxicity was evaluated using the Common Toxicity Criteria for Adverse Events v4.0.ResultsWe evaluated 55 patients (77 lesions) treated with SBRT for liver metastases. All patients had controlled primary lesions, and 28 patients had stable lesions at another site (oligo-progression). The most common primary site was the colon (36 patients), followed by the stomach (6 patients) and other sites (13 patients). The 2-year local control and progression-free survival rates were 68% and 22%, respectively. The 2- and 5-year overall survival rates were 56% and 20%, respectively. The most common adverse events were grade 1–2 fatigue, nausea, and vomiting; no grade ≥3 toxicities were observed. Univariate analysis revealed that oligo-progression associated with poor survival. ConclusionSBRT for liver oligo-recurrence and oligo-progression appears safe, with similar local control rates. For liver oligo-progression, criteria are needed to select patients in whom improved overall survival can be expected through SBRT.

CD24 blunts oral squamous cancer development and dampens the functional expansion of myeloid-derived suppressor cells

ABSTRACTCD24 expression has been implicated in the oncogenesis of multiple types of cancer and high tumor expression is considered a poor prognosis factor; however, the role of CD24 in oral cancer progression is unknown. Unlike other cancer types, we found that higher CD24 levels in human oral cancers are correlated to lower clinical stage and better overall survival. We then dissected the role of CD24 and mechanisms in oral cancer pathogenesis in mice using a genetic strategy and demonstrated that CD24 deficiency increased the oral cavity tumor burden in response to the carcinogen 4-nitroquioline 1-oxide (4-NQO). Immune profile analysis showed a significant expansion as well as increased suppressive function of myeloid-derived suppressor cells (MDSCs) in CD24−/− mice, but no apparent impairment in T cells, B cells, or dendritic cells. Further, studies with an orthotopically transplanted syngeneic squamous carcinoma model in the tongue of CD24−/− and CD24+/− mice confirmed the protective roles of CD24 against cancer. Moreover, the difference in tumor growth between CD24−/− and CD24+/− mice was blunted by immunodepletion of MDSCs. We conclude that CD24 expression impedes MDSC expansion and function, and thus slows oral cancer oncogenesis. This study is the first to examine the role of CD24 in a de novo oral cancer model, and it highlights the need to consider the immune regulatory roles of CD24 in the development of CD24-targeted therapy for cancer.

Immunomodulatory activity of nivolumab in metastatic renal cell carcinoma (mRCC): Association of biomarkers with clinical outcomes.

4500 Background: This prospective biomarker study in patients (pts) with mRCC treated with the programmed death-1 (PD-1) inhibitor antibody nivolumab assessed baseline (BL) and changes in serum chemokines, tumor T cell infiltrates (TIL), gene expression, T cell repertoire (TCR), and other biomarkers potentially associated with clinical outcomes (NCT01358721). Methods: Pts treated with 1–3 prior therapies received nivolumab 0.3, 2, or 10 mg/kg IV Q3W; treatment-naive pts received 10 mg/kg IV Q3W. Biopsies were obtained at BL and cycle 2 day 8. Overall survival (OS) parameters were estimated by Kaplan-Meier method. Tumor PD-L1 expression was measured by immunohistochemistry (28-8 antibody; Dako). PD-L1 positivity was defined as ≥ 5% tumor membrane staining in ≥ 1 biopsy; tumor burden response as ≥ 20% reduction. Gene expression data were obtained on Affymetrix U219. Results: 91 pts were treated. Of 56 evaluable BL biopsies, 32% were PD-L1+. Median OS (95% CI) was 16.4 mo (10.1–not reached [NR]) for 0.3 mg/k...

Potent Efficacy of BCL2 Inhibition with ABT-199 in High-Risk Aggressive B-Lymphoma Models When Combined with Knockdown of MCL1

Avoiding apoptosis is a hallmark of cancer. Diffuse large B-cell lymphoma (DLBCL) is the most common lymphoma and carries a poor prognosis in cases at high-risk of failing up-front R-CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone). Frequent expression of the anti-apoptotic protein BCL2 is well-described in DLBCL in numerous studies and is clear a negative prognostic marker when co-expressed with the oncogenic transcription factor c-MYC. Expression of the anti-apoptotic protein MCL1 also is found in about half of cases. BCL2 and MCL1 have redundant function in protecting cells from apoptosis.Direct inhibitors of MCL1 are not clinically available, but its short half-life permits knock-down through inhibition of cyclin-dependent kinase 9 (CDK9), which regulates transcriptional elongation. Older multi-CDK inhibitors have anti-tumor activity from loss of MCL1 but are not approved clinically due to off-target toxicities. Dinaciclib is a more potent and specific multi-CDK inhibitor with activity against CDK9. We tested dinaciclib against a panel of >20 DLBCL cell lines and found high potency, with IC50 < 20 nM in most lines. Both in vitro and in vivo, dinaciclib results in rapid loss of MCL1 protein and corresponding induction of apoptosis. Interestingly, both sensitive and resistant lines show loss of MCL1 in response to the compound. Thus, we hypothesized BCL2 activity compensates for loss of MCL1 in resistant lines. Correspondingly, over-expression of BCL2 in sensitive cells renders them completely insensitive to dinaciclib without effecting MCL1 knockdown. In 59 DLBCL cases with known BCL2 status, we assessed MCL1 protein by immunohistochemistry and found no significant difference in MCL1 expression between BCL2 positive (66%, 10/15) and negative (57%, 25/44) cases (p=0.5576).Expression of MCL1, BCL2, or both in DLBCL and the proteins’ redundant function led to the hypothesis that knockdown of MCL1 combined with direct BCL2 inhibition would synergize in the killing of high-risk DLBCL tumors. ABT-199 is a third-generation BH3 mimetic direct inhibitor of BCL2, which has shown remarkable clinical activity in chronic lymphocytic leukemia but less activity in DLBCL and other more aggressive lymphomas. We found ABT-199 combines potently and synergistically with dinaciclib in DLBCL cell lines with none of 23 lines resistant to the combination. We confirmed this in vivo using the line U2932, which is resistant in vitro to both drugs as single agents. U2932 xenografts showed dramatic reduction of tumor burden in response to the combination, a response far superior to either drug alone. We next evaluated a genetically defined immunocompetent mouse model of MYC-BCL2 double-hit lymphoma, based on MYC expression in the VavP-Bcl2 transgenic model, replicating the genetics, pathology, and aggressive clinical behavior of the human disease. Tumors from this model in vitro, interestingly, show little response to single-agent ABT-199, but the combination with dinaciclib is again synergistic. Treatment of tumor-bearing mice in vivo showed animals treated with either drug alone had no significant survival difference from vehicle-treated controls, while those treated with the combination had dramatically improved survival by Kaplan-Meier analysis (p<0.0001).Finally, we assessed the effect of combining ABT-199 with standard lymphoma chemotherapy drugs that are thought to affect MCL1 protein levels due to global effects on transcription. Doxorubicin, etoposide, and cytarabine all result in loss of MCL1 at peak in vivo attainable concentrations and synergize with ABT-199 to kill DLBCL cells otherwise resistant to the single agents. In sum, we propose therapeutic strategies combining direct inhibition of BCL2 with knockdown of MCL1 expression will be effective and tolerable for poor-prognosis lymphomas such as high-risk DLBCL and double-hit lymphoma. DisclosuresNo relevant conflicts of interest to declare.

Embelin, a small molecule quinone with a co-clinical power for castrate-resistant prostate cancer.

Embelin, a small molecule quinone with a co-clinical power for castrate-resistant prostate cancer.

Abstract B15: Increased clinical relevance of orthotopic glioma models through bioluminescence and MR imaging.

Abstract Glioblastoma multiforme (GBM) is the most common and most aggressive form of malignant primary brain tumors, affecting nearly 35,000 people in the United States. Most preclinical studies in glioma utilize survival as the primary endpoint to study, which provides limited information about disease progression, tumor burden response to treatment (a primary clinical end point). We have characterized two human glioma cell lines, Gli36 and LN827 that were modified to express luciferase in order to enable in vivo monitoring of disease progression and response to treatment using bioluminescence imaging (BLI). Anatomical magnetic resonance imaging (MRI) was also performed to directly correlate bioluminescence signal with tumor volume. Both models exhibited &amp;gt;90% tumor take-rate and responded to treatment with temozolomide, a clinical standard of care. Analysis of lifespan, tumor volume doubling times, and tumor growth delay all indicated that BLI is a reliable indicator of disease progression and response to treatment. BLI-based endpoints also showed good correlation with MR-based endpoints. These results support the use of in vivo imaging in these modified cell lines for longitudinal monitoring of tumor progression and response to therapy. Imaging was not only a reliable method for quantifying tumor burden, but enabled clinically relevant end points that could not be accessed through non-imaging means or lifespan determination alone. Further utility can be driven in these models through the use of other functional imaging end points. Citation Information: Mol Cancer Ther 2013;12(11 Suppl):B15. Citation Format: Deanne Lister, Mary Anne Meade, Tracey Woolliscroft, Deepa Balagurunathan, Erin Trachet, Wilbur Leopold, Patrick McConville. Increased clinical relevance of orthotopic glioma models through bioluminescence and MR imaging. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2013 Oct 19-23; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2013;12(11 Suppl):Abstract nr B15.

Novel hormone treatment of benign metastasizing leiomyoma: an analysis of five cases and literature review

To evaluate novel hormonal therapies in patients with unresectable benign metastasizing leiomyoma (BML) disease. Case series. National Institutes of Health (NIH). Five subjects with the diagnosis of BML based on imaging and/or histopathologic diagnosis. Four patients were treated with single or combination therapy of leuprolide acetate and/or an aromatase inhibitor. One patient was treated with an antiprogestin (CDB-2914). Response to therapy was measured by tumor burden on cross-sectional imaging employing RECIST (Response Evaluation Criteria in Solid Tumors) 1.1 guidelines. Four patients treated with single or combination therapy of leuprolide acetate and/or an aromatase inhibitor demonstrated stable disease with reduction in tumor burden. The fifth patient treated with antiprogestin (CDB-2914) had degeneration of her tumor, progression of its size, and an improvement in symptoms. Hormone treatment with GnRH agonist and/or aromatase inhibition may be a therapeutic option to reduce tumor burden in unresectable BML disease or for those patients who wish to avoid surgical intervention. RECIST 1.1 guidelines, while traditionally used to evaluate tumor response to cancer therapeutics, may be useful in evaluating BML tumor burden response to hormone therapy.

Survival Prediction in Everolimus-treated Patients with Metastatic Renal Cell Carcinoma Incorporating Tumor Burden Response in the RECORD-1 Trial

BackgroundThe phase 3 RECORD-1 study demonstrated clinical benefit of everolimus over placebo (median progression-free survival: 4.9 mo compared with 1.9 mo, p<0.001) in treatment-resistant patients with metastatic renal cell carcinoma (mRCC). However, the Response Evaluation Criteria in Solid Tumors (RECIST) objective response rate was low. ObjectiveTo explore the potential role of tumor burden response to everolimus in predicting patient survival. Design, setting, and participantsRECORD-1 patients with at least two tumor assessments (baseline and weeks 2–14) were included (n=246). Outcome measurements and statistical analysisA multivariate Cox proportional hazard model was used to assess the impact of various prognostic factors on overall survival (OS). Components of RECIST progression were explored using univariate Cox regression. Results and limitationsThe baseline sum of longest tumor diameters (SLD) and progression at weeks 2–14 were prognostic factors of OS by multivariate analysis. Univariate analysis at weeks 2–14 demonstrated that growth of nontarget lesions and appearance of new lesions were predictive of OS (p<0.001). This retrospective analysis used data from one arm of one trial; patients in the placebo arm were excluded because of confounding effects when they crossed over to everolimus. ConclusionsThis analysis identified baseline SLD as a predictive factor of OS, and the appearance of a new lesion or progression of a nontarget lesion at first assessment after baseline also affects OS in patients with mRCC treated with everolimus. Trial registrationClinicalTrials.gov: NCT00410124.

DNA methylation of circulating DNA: a marker for monitoring efficacy of neoadjuvant chemotherapy in breast cancer patients

Identification of biomarkers for monitoring efficacy of neoadjuvant chemotherapy in breast cancer patients is of utmost importance in individual tailoring of treatment and save from toxicity due to non-effective drugs. We hypothesized that methylation of circulating tumor-specific DNA may reflect changes in tumor burden in response to chemotherapy and help stratify responders from non-responders. The aim of this study was to evaluate the potential of methylation changes in circulating DNA to monitor treatment response of breast cancer patients. Six consecutive sera samples collected from 30 breast cancer patients undergoing neoadjuvant chemotherapy were analyzed for methylation status of a panel of five genes namely, BRCA1, MGMT, GSTP1, Stratifin, and MDR1. Among these five genes, BRCA1 methylation frequency was different among responders and non-responders groups. The correlation coefficients between total gene methylation with initial chemotherapy and tumor volume reduction were R(2) = 0.8 and R(2) = 0.05 in the responders and non-responders groups, respectively. Our findings warrant further development of this approach for monitoring response in patients undergoing neoadjuvant chemotherapy.

Protein Kinase C βII and PKCι/λ: Collaborating Partners in Colon Cancer Promotion and Progression

We previously showed that elevated expression of either protein kinase CbetaII (PKCbetaII) or PKCiota/lambda enhances colon carcinogenesis in mice. Here, we use novel bitransgenic mice to determine the relative importance of PKCbetaII and PKCiota/lambda in colon carcinogenesis in two complimentary models of colon cancer in vivo. Bitransgenic mice overexpressing PKCbetaII and constitutively active PKCiota (PKCbetaII/caPKCiota) or kinase-deficient, dominant-negative PKCiota (PKCbetaII/kdPKCiota) in the colon exhibit a similar increase in colon tumor incidence, tumor size, and tumor burden in response to azoxymethane (AOM) when compared with nontransgenic littermates. However, PKCbetaII/kdPKCiota mice develop predominantly benign colonic adenomas, whereas PKCbetaII/caPKCiota mice develop malignant carcinomas. In contrast, PKCbeta-deficient (PKCbeta(-/-)) mice fail to develop tumors even in the presence of caPKCiota. Our previous data indicated that PKCbetaII drives tumorigenesis and proliferation by activating beta-catenin/Apc signaling. Consistent with this conclusion, genetic deletion of PKCbeta has no effect on spontaneous tumorigenesis in Apc(min/+) mice. In contrast, tissue-specific knockout of PKClambda significantly suppresses intestinal tumor formation in Apc(min/+) mice. Our data show that PKCbetaII and PKCiota/lambda serve distinct, nonoverlapping functions in colon carcinogenesis. PKCbetaII is required for AOM-induced tumorigenesis but is dispensable for tumor formation in Apc(Min/+) mice. PKCiota/lambda promotes tumor progression in both AOM- and Apc(min/+)-induced tumorigenesis. Thus, PKCbetaII and PKCiota, whose expression is elevated in both rodent and human colon tumors, collaborate to drive colon tumor formation and progression, respectively.

Clinical significance of serial measurement of the serum levels of soluble interleukin-2 receptor and soluble CD8 in malignant lymphoma.

We serially measured the serum levels of soluble interleukin-2 receptor (sIL-2R) and soluble CD8 (sCD8) in 36 patients with malignant lymphoma (33 non-Hodgkin's lymphoma cases and three Hodgkin's disease cases). The level of serum sIL-2R was significantly elevated in patients with active disease (18) compared to those in remission (18), and correlated with the clinical stage of the lymphoma. The temporal profile of the sIL-2R level reliably represented the disease status, which was judged clinically, during the course of the disease. In three patients, the tumor bulk paralleled the sIL-2R level. On the other hand, a less significant correlation was found between the serum sCD8 level and disease activity. The serial measurement of sCD8 appeared to be less useful for monitoring the disease activity, although there was a significant correlation between the sCD8 and sIL-2R levels. This study indicates that serial measurement of the serum sIL-2R level may be useful for monitoring the tumor burden in response to treatment and for early detection of disease progression in malignant lymphoma.