Therapy Response Monitoring Research Articles

Phosphorus spectroscopy in acute TBI demonstrates metabolic changes that relate to outcome in the presence of normal structural MRI

Metabolic dysfunction is a key pathophysiological process in the acute phase of traumatic brain injury (TBI). Although changes in brain glucose metabolism and extracellular lactate/pyruvate ratio are well known, it was hitherto unknown whether these translate to downstream changes in ATP metabolism and intracellular pH. We have performed the first clinical voxel-based in vivo phosphorus magnetic resonance spectroscopy (31P MRS) in 13 acute-phase major TBI patients versus 10 healthy controls (HCs), at 3T, focusing on eight central 2.5 × 2.5 × 2.5 cm3 voxels per subject. PCr/γATP ratio (a measure of energy status) in TBI patients was significantly higher (median = 1.09) than that of HCs (median = 0.93) (p < 0.0001), due to changes in both PCr and ATP. There was no significant difference in PCr/γATP between TBI patients with favourable and unfavourable outcome. Cerebral intracellular pH of TBI patients was significantly higher (median = 7.04) than that of HCs (median = 7.00) (p = 0.04). Alkalosis was limited to patients with unfavourable outcome (median = 7.07) (p < 0.0001). These changes persisted after excluding voxels with > 5% radiologically visible injury. This is the first clinical demonstration of brain alkalosis and elevated PCr/γATP ratio acutely after major TBI. 31P MRS has potential for non-invasively assessing brain injury in the absence of structural injury, predicting outcome and monitoring therapy response.

Preclinical evaluation of 99mTc direct labeling ZHER2:V2 for HER2 positive tumors imaging.

The present study aimed to label ZHER2:V2 with technetium-99m (99mTc) using a simple method and to evaluate its clinical potential as a diagnostic probe for human epidermal growth factor receptor type 2 (HER2)-positive tumors. The ZHER2:V2 (Affibody molecule of ZHER2:2395-C, which is based on the ZHER2:342 binding sequence with C-terminal engineered cysteine) with C-terminal chelating sequence GGGC was designed and labeled with 99mTc. The 99mTc-ZHER2:V2 labeling efficiency was analyzed. The cellular uptake, retention and binding affinity, and the stability of the probe were examined in vitro. 99mTc-ZHER2:V2 biodistribution analysis and imaging were performed in BALB/c nude mice bearing SKOV3 (HER2-overexpression) xenografts. Furthermore, imaging of the probe was performed in MCF-7 (HER2 low-expression) xenografts. The 99mTc-ZHER2:V2 labeling efficiency was identified as 98.99±0.99% (n=6), and was stable in physiological saline and fresh human serum at 37°C in vitro. The cellular uptake peak of SKOV3 cells at 24 h was 6.15±0.18%, the cellular retention ratio of the probe was 48.58±4.52% at 6 h following interrupted incubation, and ~70% of 99mTc-ZHER2:V2 was membrane bound following 24 h. 99mTc-ZHER2:V2 was blocked by excess amounts of unlabeled ZHER2:V2 in SKOV3 cells. 99mTc-ZHER2:V2 exhibited high distribution (10.07% ID/g) in SKOV3 ×enografts at 6 h following injection. The single photon emission computed tomography (SPECT) imaging revealed clear localization of 99mTc-ZHER2:V2 in the SKOV3 ×enografts at 4 h. However, there was low uptake in MCF-7 tumors on the SPECT images. The SKOV3 ×enograft imaging could be blocked by excess amounts unlabelled ZHER2:V2. 99mTc-ZHER2:V2 is an easy and quick labeling method, with high labeling yields, and radiochemical purity. 99mTc-ZHER2:V2 is a promising probe for the diagnosis of HER2-overexpression tumors and the monitoring of therapy response.

Investigation of altered urinary metabolomic profiles of invasive ductal carcinoma of breast using targeted and untargeted approaches.

Invasive ductal carcinoma (IDC) is a type of breast cancer, usually detected in advanced stages due to its asymptomatic nature which ultimately leads to low survival rate. Identification of urinary metabolic adaptations induced by IDC to understand the disease pathophysiology and monitor therapy response would be a helpful approach in clinical settings. Moreover, its non-invasive and cost effective strategy better suited to minimize apprehension among high risk population. This study aims toward investigating the urinary metabolic alterations of IDC by targeted (LC-MRM/MS) and untargeted (GC-MS) approaches for the better understanding of the disease pathophysiology and monitoring therapy response. Urinary metabolic alterations of IDC subjects (63) and control subjects (63) were explored by targeted (LC-MRM/MS) and untargeted (GC-MS) approaches. IDC specific urinary metabolomics signature was extracted by applying both univariate and multivariate statistical tools. Statistical analysis identified 39 urinary metabolites with the highest contribution to metabolomic alterations specific to IDC. Out of which, 19 metabolites were identified from targeted LC-MRM/MS analysis, while 20 were identified from the untargeted GC-MS analysis. Receiver operator characteristic (ROC) curve analysis evidenced 6 most discriminatory metabolites from each type of approach that could differentiate between IDC subjects and controls with higher sensitivity and specificity. Furthermore, metabolic pathway analysis depicted several dysregulated pathways in IDC including sugar, amino acid, nucleotide metabolism, TCA cycle etc. CONCLUSIONS: Overall, this study provides valuable inputs regarding altered urinary metabolites which improved our knowledge on urinary metabolomic alterations induced by IDC. Moreover, this study identified several dysregulated metabolic pathways which offer further insight into the disease pathophysiology.

Intravital microscopy of osteolytic progression and therapy response of cancer lesions in the bone.

Intravital multiphoton microscopy (iMPM) in mice provides access to cellular and molecular mechanisms of metastatic progression of cancers and the underlying interactions with the tumor stroma. Whereas iMPM of malignant disease has been performed for soft tissues, noninvasive iMPM of solid tumor in the bone is lacking. We combined miniaturized tissue-engineered bone constructs in nude mice with a skin window to noninvasively and repetitively monitor prostate cancer lesions by three-dimensional iMPM. In vivo ossicles developed large central cavities containing mature bone marrow surrounded by a thin cortex and enabled tumor implantation and longitudinal iMPM over weeks. Tumors grew inside the bone cavity and along the cortical bone interface and induced niches of osteoclast activation (focal osteolysis). Interventional bisphosphonate therapy reduced osteoclast kinetics and osteolysis without perturbing tumor growth, indicating dissociation of the tumor-stroma axis. The ossicle window, with its high cavity-to-cortex ratio and long-term functionality, thus allows for the mechanistic dissection of reciprocal epithelial tumor-bone interactions and therapy response.

Radioiodinated Pentixather for SPECT Imaging of Expression of the Chemokine Receptor CXCR4 in Rat Myocardial-Infarction-Reperfusion Models.

The purpose of this study is to develop a specific CXCR4-targeting radioiodinated agent (125I- or 131I-pentixather) for single-photon-emission-computed-tomography (SPECT) imaging of CXCR4 expression in myocardial-infarction-reperfusion (MI/R) rat models. After SPECT-CT imaging with 125I-pentixather at 4, 12, and 36 h and 3 and 7 days after MI/R, the models were validated by ex vivo autoradiography, TTC staining, and immunohistochemistry and in vivo echocardiography and classical 99mTc-MIBI perfusion imaging. The SPECT-CT images showed that the infarcted myocardium (IM) could be visualized with high quality as early as 4 h and reached the maximum at 3 days after MI/R and that CXCR4 upregulation was still visible at 7 days after MI/R. In the biodistribution study, high uptakes in the IM (0.99 ± 0.13, 1.52 ± 0.29, 1.75 ± 0.22, 1.94 ± 0.27, and 0.61 ± 0.14% ID/g at 4, 12, and 36 h and 3 and 7 days after MI/R, respectively) were observed that were much higher than that of normal myocardium. The highest uptake was reached at 3 days after MI/R, which agreed well with the SPECT results. In addition, the radioactivity uptakes of the IM in both the biodistribution and SPECT imaging could be blocked effectively by excess amounts of AMD3465, indicating the high specificity of radioiodinated pentixather to CXCR4. On the basis of its promising properties, 125I-pentixather may serve as a powerful CXCR4-expression diagnostic probe for evaluating lesions and monitoring therapy responses in patients with cardiovascular diseases.

Abstract 3546: Extracellular vesicles and exosome-associated microRNAs in squamous cell carcinoma of the head and neck disrupt dendritic cell differentiation and maturation

Abstract Squamous cell carcinomas (SCCs) remain among the most common malignancies of the head and neck region. Plasma microRNAs (miRNAs) are appealing biomarker candidates for diagnosis or therapy response monitoring since they may be associated with clinical and pathological features of the disease. Increasing evidence also points to a role for these molecules, mostly when transported by extracellular vesicles (EVs), in signaling between cancer and immune cells. The aims of this study are to search for potential miRNA biomarkers for SCCs in plasma, to evaluate the presence of these markers within EVs using SCC-derived cell lines as study models and to study the effect of EVs on monocyte-derived dendritic cells functions. Total RNA was isolated from plasma samples from head and neck SCC patients and healthy donors following optimized protocols. EVs from the culture medium of SCC cell lines were collected by differential centrifugation and visualized by transmission electron microscopy. The expression profile of miRNAs in plasma and EVs was evaluated by qRT-PCR. CD14+ cells from healthy donors were selected from peripheral blood using magnetic selection columns. Monocyte-derived immature dendritic cells were obtained following CD14+ cells treatment with human recombinant IL-4 and GM-CSF for six days and the maturation signal consisted on treatment of immature dendritic cells with LPS for 24 hours. Both treatments were carried out either in the presence or absence of EVs. Immunophenotyping of monocytes and monocyte-derived dendritic cells was based on the detection and expression levels of cell surface markers CD14, CD33, CD45, CD80, CD86, CD209 and HLA-DR by flow cytometry. A subset of miRNAs was consistently detected in SCC patients' plasma and EVs. Among these, miR-24 is of special interest since it has been associated with antigen processing and presentation by dendritic cells. The percentage of CD14+ cells expressing CD33 when cultured in the presence of EVs was significantly lower, and the same effect was seen for the CD209 and CD80 markers, suggesting alterations of antigen presentation functions. The percentage of cells expressing HLA-DR was similar both when CD14+ cells were cultured in the presence or without the addition of EVs, but the level of HLA-DR expression, as measured by fluorescence intensity, was lower when EVs were present, following both differentiation and maturation signals. The detection of miRNAs both in plasma and in association with EVs corroborates their potential as cancer biomarkers but also their possible implication in cell signaling. Differences in surface markers of monocyte-derived dendritic cells in the presence of EVs suggest an effect of EV content, including miRNAs, on differentiation and maturation processes, essential aspects for the proper function of dendritic cells in the tumor microenvironment. Citation Format: Luciana C. Marti, Elisangela P. Silva, Mariana B. Rizzo, Rossana V. Lopez, Otavio A. Curioni, Raquel A. Moyses, Fabio D. Nunes, Patricia Severino. Extracellular vesicles and exosome-associated microRNAs in squamous cell carcinoma of the head and neck disrupt dendritic cell differentiation and maturation [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 3546.

Abstract 1165: A tissue-engineered bone mimetic in vitro model for monitoring metastatic PCa growth and therapy response

Abstract Despite recent advances in prostate cancer (PCa) treatment, the outcome of metastatic disease remains frequently fatal and the underlying biology poorly understood. Thus, the development of clinically relevant in vitro models to monitor PCa biology in organotypic bone-like environment is critical to uncover mechanisms of therapy resistance and identify more effective treatments. To establish a bone-mimetic culture, we combined the following components: (i) bioactive osteoblasts depositing bone-like calcified extracellular matrix, (ii) complex 3D surface geometries, (iii) multicellular tumor application as spheroids/organoids, and (iv) applicability for live-cell microscopy to monitor the development of lesions over time. Calcified polycaprolactone (PCL) scaffolds were functionalized with bone-derived human mesenchymal stem cells (hMSCs) differentiated to osteoblasts, to generate a 3D niche-like calcified scaffold. PCa spheroids (PC3, C4-2B, patient-derived xenografts) were on-planted and their growth and invasion longitudinally monitored by advanced microscopy. PCa spheroids seeded on the organotypic bone model could be maintained and expanded over weeks, sufficient for monitoring therapy response to docetaxel, a first-line therapy for advanced PCa. The bone mimetic culture further revealed resistance to docetaxel mainly at the invasive edges, through a mechanism depending on the presence of osteoblasts. Thus, this 3D in vitro organotypic model will be suitable for dissecting the physical and molecular PCa cell-osteoblast interaction involved in PCa growth and therapy resistance. Citation Format: Claudia Paindelli, Dietmar Hutmacher, Peter Friedl, Eleonora Dondossola. A tissue-engineered bone mimetic in vitro model for monitoring metastatic PCa growth and therapy response [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 1165.

18F-FDG PET/CT in the evaluation of cancer cervix: Where do we stand today?

The incidence of gynecological malignancies is on the rise partly because of the availability of screening programmes, awareness, higher technological advancements, and availability of better medical care. Early diagnosis of any malignancy leads to prompt treatment. Use of 18Fluorine-Fluorodeoxyglucose (F-FDG) PET/CT in the treatment and follow-up of patients with Ca cervix considerably improves patient management. The primary diagnosis of Ca cervix is made either by biopsy of a visible tumor on the cervix or by a cone biopsy of a nonvisible malignant cervical focus. The staging procedure is purely clinical (i.e. gynecologic examination under general anesthesia) according to the International Federation of Gynaecology and Obstetrics classification. Earlier, with the nonavailability of sophisticated medical equipment and imaging specialists, oncologists relied heavily on clinical examination. However, anatomical and functional imaging has been proven to be considerably superior in understanding parametrial involvement and nodal/distant metastases in the cancer cervix than clinical examination alone. Data are evolving on the usage of F-FDG PET/CT in initial staging, treatment planning, and monitoring therapy response for gynecological malignancies. Prognostic information derived from the primary lesion such as the maximum standardized uptake value, metabolic tumor volume, and extent of para-aortic nodal metastatic disease plays a critical role in tailoring therapy on the basis of patient tumor-specific factors rather than on International Federation of Gynaecology and Obstetrics stage alone. Thus, F-FDG PET/CT needs to be listed not only under the panel of pretherapy investigations for Ca cervix but also for recurrence and therapy response assessments. It allows a more confident approach to patient management at initial staging, especially in terms of the decision to choose surgical versus palliation measures.

The importance of intestinal ultrasound and elastographic techniques in inflammatory bowel diseases.

Inflammatory bowel diseases have an important impact upon the economic and social status due to their increasing incidenceand prevalence, often affecting young people. At the moment, the therapeutic goal goes beyond the improvementof symptoms and laboratory parameters, being represented by endoscopic mucosal healing, changing the disease's naturalhistory. Even though endoscopy is the gold standard for the assessment of mucosal healing, it is an invasive maneuver and itlacks good repeatability. These patients require frequent evaluation; therefore, interest for noninvasive techniques has risen.As a consequence, the importance of intestinal ultrasound has increased lately and recent studies support its use to assess thedegree of inflammation, to differentiate between remission and relapse, to monitor therapy response and guide treatment, toevaluate prognosis, and to diagnose complications. Another promising noninvasive imagistic technique is elastography whichhas gained interest because of its capacity to discriminate between inflammatory and fibrotic tissue, taking into account thedifferent therapeutic options for the fibrotic strictures compared to inflammatory processes. This review summarizes the actualrecommendations regarding the use of intestinal ultrasound and elastographic techniques for the diagnosis and monitoring ofinflammatory bowel diseases.

Surface-Modified Shortwave-Infrared-Emitting Nanophotonic Reporters for Gene-Therapy Applications.

Gene therapy is emerging as the next generation of therapeutic modality with United States Food and Drug Administration approved gene-engineered therapy for cancer and a rare eye-related disorder, but the challenge of real-time monitoring of on-target therapy response remains. In this study, we have designed a theranostic nanoparticle composed of shortwave-infrared-emitting rare-earth-doped nanoparticles (RENPs) capable of delivering genetic cargo and of real-time response monitoring. We showed that the cationic coating of RENPs with branched polyethylenimine (PEI) does not have a significant impact on cellular toxicity, which can be further reduced by selectively modifying the surface characteristics of the PEI coating using counter-ions and expanding their potential applications in photothermal therapy. We showed the tolerability and clearance of a bolus dose of RENPs@PEI in mice up to 7 days after particle injection in addition to the RENPs@PEI ability to distinctively discern lung tumor lesions in a breast cancer mouse model with an excellent signal-to-noise ratio. We also showed the availability of amine functional groups in the collapsed PEI chain conformation on RENPs, which facilitates the loading of genetic cargo that hybridizes with target gene in an in vitro cancer model. The real-time monitoring and delivery of gene therapy at on-target sites will enable the success of an increased number of gene- and cell-therapy products in clinical trials.

Epigenetic Modifications as Biomarkers of Tumor Development, Therapy Response, and Recurrence across the Cancer Care Continuum.

Aberrant epigenetic modifications are an early event in carcinogenesis, with the epigenetic landscape continuing to change during tumor progression and metastasis—these observations suggest that specific epigenetic modifications could be used as diagnostic and prognostic biomarkers for many cancer types. DNA methylation, post-translational histone modifications, and non-coding RNAs are all dysregulated in cancer and are detectable to various degrees in liquid biopsies such as sputum, urine, stool, and blood. Here, we will focus on the application of liquid biopsies, as opposed to tissue biopsies, because of their potential as non-invasive diagnostic tools and possible use in monitoring therapy response and progression to metastatic disease. This includes a discussion of septin-9 (SEPT9) DNA hypermethylation for detecting colorectal cancer, which is by far the most developed epigenetic biomarker assay. Despite their potential as prognostic and diagnostic biomarkers, technical issues such as inconsistent methodology between studies, overall low yield of epigenetic material in samples, and the need for improved histone and non-coding RNA purification methods are limiting the use of epigenetic biomarkers. Once these technical limitations are overcome, epigenetic biomarkers could be used to monitor cancer development, disease progression, therapeutic response, and recurrence across the entire cancer care continuum.

Novel frontiers of dedicated molecular imaging in breast cancer diagnosis

Breast cancer (BC) is the most common cancer in women worldwide. In the last years, the contribution of nuclear medicine has grown based on the use of dedicated molecular breast devices for diagnosis and biopsy. Recent technical improvements have been achieved in order to increase the detection of smaller breast lesions using lower doses of radiotracers as well as to facilitate accurate biopsy sampling. Furthermore, new prototypes have been developed combining anatomic and functional imaging. Although the gamma-emitting 99m Tc-sestamibi ( 99m Tc-MIBI) and the positron-emitting 18 F-fluorodeoxyglucose ( 18 F-FDG) are the most widely used radiotracers, several new tracers have been investigated to target more specific biologic features of BC like proliferation, angiogenesis and tumour receptor status. Dedicated molecular breast devices have been introduced as an adjunct imaging tool to mammography (MG) and ultrasound (US) in the clinical work-up for BC. Additionally, due to the increased interest in molecular tumour subtype analysis and ribonucleic acid (RNA)-based gene expression profiling tests in the routine clinical practice, a possible new clinical application of dedicated breast imaging concerns locally advanced BC, principally in order to visualise intra-tumour metabolic heterogeneity enabling selection of areas with highest tracer uptake (vital tissue) for core needle biopsy. Hence, it will be possible to more adequately tailor the individual treatment, also enabling therapy response monitoring. This review evaluates the current and future perspectives as well as the shortcomings of breast imaging using dedicated nuclear medicine devices.

Exosome-associated miRNA profile as a prognostic tool for therapy response monitoring in multiple sclerosis patients.

Multiple sclerosis (MS) is an autoimmune pathology leading to neurodegeneration. Because of the complexity and heterogenic etiology of this disease, diagnosis and treatment for individual patients are challenging. Exosome-associated microRNAs (miRNAs) have recently emerged as a new class of diagnostic biomarkers involved in both autoimmune and neurologic disorders. Interesting new evidence has emerged showing that circulating miRNAs are dysregulated in MS body fluids, including serum, plasma, and cerebrospinal fluid. We hypothesized that exosome-associated miRNAs could present a readily accessible blood-based assay for MS disease. We detected expression of miRNAs by quantitative PCR on a small cohort of MS patients. We analyzed circulating exosome-associated miRNAs of MS patients before and after therapy and found that 14 exosome-associated miRNAs were significantly down-regulated, while 2 exosome-associated miRNAs were significantly up-regulated in IFN-β-treated relapsing-remitting MS patients with response to therapy compared to those without response. We identified a serum miRNA panel that could be used to monitor the response to IFN-β therapy. Overall, these data suggest that circulating exosome-associated miRNA profiling could represent an easily detectable biomarker of disease and treatment response.-Manna, I., Iaccino, E., Dattilo, V., Barone, S., Vecchio, E., Mimmi, S., Filippelli, E., Demonte, G., Polidoro, S., Granata, A., Scannapieco, S., Quinto, I., Valentino, P., Quattrone, A. Exosome-associated miRNA profile as a prognostic tool for therapy response monitoring in multiple sclerosis patients.

Decreased IgG4 ACPA levels in responders and increased CD1c+ classical dendritic cells in non-responders of patients with rheumatoid arthritis under therapy.

The treatment options for patients suffering from rheumatoid arthritis expanded over the last years. However, reliable biomarkers to guide therapy decisions are still warranted. Therefore, we here evaluated the value of antibodies against citrullinated peptide antigens (ACPA) IgG subclasses and peripheral blood antigen presenting cells as biomarkers to monitor and predict therapy response of patients with rheumatoid arthritis. Thirty-four ACPA-positive RA patients were enrolled and monitored for 3months after therapy begin. ACPA IgG1 and IgG4 serum levels were quantified by ELISA. Phenotyping of the B cell, monocytic, and dendritic cell lineages was performed via flow cytometry. Three months after therapy begin, the responders showed a significant decrease in IgG4 ACPA levels, and this was independent of the individual treatment regimen. The non-responders showed a significant increase in CD1c+ classical dendritic cells (cDC). Furthermore, the baseline disease activity score 28 and the baseline percentage of cDC allowed for some prediction of future therapy responses. We here suggest IgG4 ACPA levels as biomarkers to monitor therapy response in RA. The increase in CD1c+ cDC among non-responders to therapy remains enigmatic and requires future elucidation of the underlying mechanisms.

Clinical relevance of size selection of circulating DNA

: Circulating cell-free DNA (cfDNA) is a non-invasive and powerful detection, diagnosis, prognosis, therapy response monitoring and recovery prediction tool, which opens new possibilities in fields of prenatal care, tumor therapy and transplant medicine. It is released from cells undergoing apoptosis and necrosis or by active secretion. Depending on the source and mechanisms of release, cfDNA is shed as fragments with different genetic and epigenetic profiles and in various lengths into the bloodstream. High- and low-weight cfDNA molecules can be detected in the different human body fluids. In pathological states, cfDNA size patterns have been found to vary from cfDNA released under healthy physiological conditions. In the following paragraphs, we describe methods and different technical platforms, to enrich, isolate and identify size profiles of cfDNA detected in human plasma and serum.

Identification of clinically relevant cytomegalovirus infections in patients with inflammatory bowel disease

Several lines of evidence indicate that cytomegalovirus infection can be substantially associated with onset of inflammatory bowel disease, especially in patients refractory to immunosuppressive treatment. As cytomegalovirus is widely spread in the population, here we present a quantitative detection system suitable to differentiate clinically relevant cytomegalovirus infection from common latent cytomegalovirus. Using a quantitative real-time PCR approach, cytomegalovirus viral load was evaluated in 917 formalin-fixed and paraffin-embedded colon biopsy samples of 136 patients diagnosed with inflammatory bowel disease. Besides initial cytomegalovirus testing, the PCR system was also used to monitor therapy response after antiviral treatment. Cytomegalovirus DNA was detected in 37 patients (27%) with varying viral loads ranging from 5 to 8.7 × 105 copies/105 cells. Thereof, 13 patients (35%) received an antiviral treatment with 12 of them going into remission (92%). Later, five patients displayed a relapse and three patients who agreed to restart antiviral treatment again showed positive therapy response. A retrospective comparison of viral loads with antiviral therapy response revealed a threshold of 600 cytomegalovirus copies/105 cells as indicative for clinically relevant infection. Of note, sensitivity of cytomegalovirus detection by immunohistochemistry was found to be insufficient to reliably identify antiviral therapy responders. In conclusion, quantitative real-time PCR using formalin-fixed biopsy samples is suitable for detection of cytomegalovirus infection in tissue samples of patients with inflammatory bowel disease. Moreover, it allows the definition of a viral load threshold, predictive for clinical relevance concerning antiviral therapy response.

Thymidine Metabolism as a Confounding Factor for 3'-Deoxy-3'-18F-Fluorothymidine Uptake After Therapy in a Colorectal Cancer Model.

Noninvasive monitoring of tumor therapy response helps in developing personalized treatment strategies. Here, we performed sequential PET and diffusion-weighted MRI to evaluate changes induced by a FOLFOX-like combination chemotherapy in colorectal cancer xenografts, to identify the cellular and molecular determinants of these imaging biomarkers. Methods: Tumor-bearing CD1 nude mice, engrafted with FOLFOX-sensitive Colo205 colorectal cancer xenografts, were treated with FOLFOX (5-fluorouracil, leucovorin, and oxaliplatin) weekly. On days 1, 2, 6, 9, and 13 of therapy, tumors were assessed by in vivo imaging and ex vivo analyses. In addition, HCT116 xenografts, which did not respond to the FOLFOX treatment, were imaged on day 1 of therapy. Results: In Colo205 xenografts, FOLFOX induced a profound increase in uptake of the proliferation PET tracer 3'-deoxy-3'-18F-fluorothymidine (18F-FLT) accompanied by increases in markers for proliferation (Ki-67, thymidine kinase 1) and for activated DNA damage response (γH2AX), whereas the effect on cell death was minimal. Because tracer uptake was unaltered in the HCT116 model, these changes appear to be specific for tumor response. Conclusion: We demonstrated that 18F-FLT PET can noninvasively monitor cancer treatment-induced molecular alterations, including thymidine metabolism and DNA damage response. The cellular or imaging changes may not, however, be directly related to therapy response as assessed by volumetric measurements.

Abstract P2-02-10: Circulating level of GP88/Progranulin is associated with clinical outcome and overall survival in stage 4 breast cancer patients

Abstract Monitoring of disease status in metastatic breast cancer (MBC) patients is a necessary step for an optimal management of patients during and post-therapy. Imaging technologies are the methods of choice in the standard of care to monitor therapy response and disease status in MBC patients. These methods are expensive, time-consuming and have limited sensitivity for real time monitoring. Measurements of circulating tumor markers CA15-3, CA125 and CEA have contributed, albeit with limitation, minimally invasive methods for MBC disease management. It is our hypothesis that measuring biomarkers involved in tumor biological processes may provide better evaluation of the disease state and thus aid real-time clinical management of MBC patients. Thus, addition of such new circulating disease biomarkers may improve the management of MBC patients. The 88kDa glycoprotein Progranulin (GP88/PGRN) fit these criteria. GP88/PGRN is expressed in tumor tissue and not in normal mammary tissue counterpart and secreted in the circulation of BC patients. Biological studies have established GP88/PGRN as a critical driver of BC cell proliferation, survival, invasiveness and drug resistance. Clinical studies have demonstrated that high tumor GP88/PGRN expression was prognostic for recurrence and that breast cancer patients had a statistically elevated GP88/PGRN serum level compared to healthy individuals. In the present study, we examined whether GP88/PGRN serum levels were elevated in MBC patients and whether GP88/PGRN circulating levels were correlated with patient clinical outcome and overall survival. Under an IRB approved protocol at the University of Maryland Greenebaum Comprehensive Cancer Center, 101 stage 4 BC patients undergoing standard of care therapy and meeting the inclusion criteria were consented and enrolled. MBC patients' demographics, clinical and disease characteristics and therapies were collected as part of the study. Blood samples were collected from each patient at specific times at follow-up visits during and post-therapy. The prepared serum was stored at -80C until tested for GP88 using a GP88 enzyme linked immunoassay developed in our laboratory. Statistical analysis using Kaplan-Meier functions established whether there was a correlation between GP88/PGRN serum level and overall survival in MBC patients. MBC patients with distinct survival characteristics (P=0.0002) could be stratified based on their circulating GP88/PGRN levels. Analysis of this association was carried out in MBC patients based on their age, race, tumor characteristics, receptor status and metastatic burden (number and sites of metastasis) and will be reported. We conclude that circulating levels of GP88/PGRN in MBC patients are correlated with overall survival and that monitoring circulating GP88/PGRN levels would provide additional information and valuable insight into real-time MBC disease status. This work was supported by grant R43 CA 210817-01A1 to GS. Citation Format: Serrero G, Hawkins D, Hicks D, Rosenblatt P, Tait N, Yue B, Tkaczuk K. Circulating level of GP88/Progranulin is associated with clinical outcome and overall survival in stage 4 breast cancer patients [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P2-02-10.

Role of 18F-FDG PET/CT in Renal Cyst Infection

Cyst infection (CI) is a severe complication of cystic renal disorders, notably in autosomal-dominant polycystic kidney disease (ADPKD), and constitutes a diagnostic challenge because of the lack of specific clinical manifestations and limitations of conventional imaging methods. The role of 18fluorodeoxyglucose positron-emission computed tomography combined with computed tomography (18F-FDG PET/CT) in renal CI is reviewed. Recent reports suggest that 18F-FDG PET/CT is the best tool for CI detection. This technique has been demonstrated to play a role not only in the identification of CI, but also in the guidance of invasive procedures, in the detection of other infectious or even incidental neoplastic foci, and in monitoring therapy response. This article aims to review the role of 18F-FDG PET/CT in renal CI, particularly in the context of ADPKD, compare this technique with conventional radiological and nuclear medicine methods, and discuss future perspectives in the approach to such a diagnostic challenge.

PET Imaging of VCAM-1 Expression and Monitoring Therapy Response in Tumor with a 68Ga-Labeled Single Chain Variable Fragment.

Vascular cell adhesion molecule-1 (VCAM-1) is a transmembrane glycoprotein closely related to tumorigenicity as well as tumor metastasis. It is also a well-known candidate for detecting tumors. LY2409881, an IKKβ inhibitor, could induce apoptosis of VCAM-1 positive cells. Our purpose is to prepare a novel tracer to evaluate its feasibility of detecting VCAM-1 expression and monitoring LY2409881 tumor curative effect. The tracer was prepared by conjugating the single chain variable fragment (scFv) of VCAM-1 and NOTA-NHS-ester and then labeled with 68Ga. 68Ga-NOTA-VCAM-1scFv was successfully prepared with high radiochemical yield. VCAM-1 overexpression and underexpression melanoma cell lines, B16F10 and A375m, were used in this study. The results of microPET/CT imaging in small animals indicated that the uptake of 68Ga-NOTA-VCAM-1scFv in B16F10 tumor was much higher than that of A375m, which was also confirmed by the biodistribution and autoradiography results. LY2409881 inhibits the growth of B16F10 melanoma in vivo by inducing dose- and time-dependent growth inhibition and apoptosis of the cells. The LY2409881 treated group and DMSO control group were established and imaged by microPET/CT. In the LY2409881 group, uptake of the tracer in tumor was decreased at the first week, and then gradually recovered to the initial level. In DMSO control, the uptake of the tracer remained at the same level during the whole time. The results suggested that LY2409881 inhibits the expression of VCAM-1 and suppresses tumor growth. 68Ga-NOTA-VCAM-1scFv, an easily synthesized probe, has a potential clinical application in the visual monitoring of IKKβ inhibitor intervention on VCAM-1 positive tumors.