The genomic profiling of high-risk smoldering myeloma patients treated with an intensive strategy unveils potential markers of resistance and progression

Smoldering multiple myeloma (SMM) precedes multiple myeloma (MM). The risk of progression of SMM patients is not uniform, thus different progression-risk models have been developed, although they are mainly based on clinical parameters. Recently, genomic predictors of progression have been defined for untreated SMM. However, the usefulness of such markers in the context of clinical trials evaluating upfront treatment in high-risk SMM (HR SMM) has not been explored yet, precluding the identification of baseline genomic alterations leading to drug resistance. For this reason, we carried out next-generation sequencing and fluorescent in-situ hybridization studies on 57 HR and ultra-high risk (UHR) SMM patients treated in the phase II GEM-CESAR clinical trial (NCT02415413). DIS3, FAM46C, and FGFR3 mutations, as well as t(4;14) and 1q alterations, were enriched in HR SMM. TRAF3 mutations were specifically associated with UHR SMM but identified cases with improved outcomes. Importantly, novel potential predictors of treatment resistance were identified: NRAS mutations and the co-occurrence of t(4;14) plus FGFR3 mutations were associated with an increased risk of biological progression. In conclusion, we have carried out for the first time a molecular characterization of HR SMM patients treated with an intensive regimen, identifying genomic predictors of poor outcomes in this setting.

NUT carcinoma of the mandible in a child: case report and systematic review

Nuclear protein of the testis (NUT) carcinoma is a rare, undifferentiated carcinoma that is characterized by NUTM1 gene rearrangements. Patients with NUT carcinoma have an overall survival of approximately 5% at 5 years despite a multimodal treatment approach. This report illustrates the management of mandibular NUT carcinoma in a pediatric patient, complemented by a systematic review of head and neck NUT carcinoma. A 5-year-old female presented with an enlarging jaw mass that was diagnosed as BRD4-NUTM1 carcinoma and was treated with hemimandibulectomy and chemoradiation. She remains disease-free 21 months after completion of therapy. A total of 63 patient cases reported in 34 articles were identified in the review. Only 26.9% (14/52) of tumors were correctly diagnosed initially as NUT carcinoma, whereas 73.1% (38/52) were incorrectly diagnosed as another malignancy; the initial diagnosis was not reported for 11 patients. The mandibular tumor subtype was among the rarest reported (n = 1; 1.6%). Combination therapy, including surgery and chemoradiation, was the most common treatment (55.2%). The patient case presented here is a novel case of pediatric mandibular NUT carcinoma. Due to the poor overall survival of patients with NUT carcinoma, aggressive upfront resection with 2-cm margins followed by adjuvant chemoradiation is advocated.

Abstract LB-239: Co-expression analysis reveals tumor biology and prognostic biomarkers in pancreatic ductal adenocarcinoma

Despite extensive biological and clinical studies, including comprehensive profiling using genomics and transcriptomics efforts, pancreatic ductal adenocarcinoma (PDAC) remains a devastating disease, with poor survival and no effective therapies to date. Development of new tools and experimental methods are driven by the urge of identification of better sensitive and specific biomarkers for this disease. In recent years, multiple statistical methods and freely available tools have been developed and can extrapolate important features in high-throughput data, e.g. pinpointing genes associated with clinical parameters such as cancer status or patient survival. In this context, network topology based on co-expression has extensively been used to identify subsets of gene-disease relations. Correlation networks are emerging as a powerful approach to infer tumor biology from -omics data and to prioritize candidate genes as biomarkers or drug targets. In this study, we applied a weighted co-expression analysis to the proteome of 20 surgically resected PDAC specimens. Next, modules were associated to clinical end points to underline prognostic markers.This co-expression analysis yielded 12 consensus modules, subsequently analyzed by gene set enrichment analysis (GSEA) to characterize the associated biology. The modules covered a wide range of biological terms, and the most frequently occurring terms were those implicated in metabolic processes in the context of mitochondrial compartment. More specifically, five modules consisted predominantly of immune system and defense and four modules were associated with epithelial to mesenchymal transition processes. Notably, one module enriched for metabolic processes and epithelial-mesenchymal-transition (EMT) was significantly associated with overall survival (p=0.01) and disease-free survival (p = 0.03). The prognostic value of three proteins (SPTBN1, KHSRP and PYGL) belonging to this module was confirmed using immunohistochemistry in a cohort of 82 resected patients. Risk score evaluation of the prognostic signature confirmed the association to OS in multivariate analysis. Finally, immunofluorescence confirmed co-expression of SPTBN1 and KHSRP in Hs766t PDAC cells. Taken together, our results demonstrate that an EMT - metabolic module is associated with prognosis after surgical resection of PDAC patients and the module's proteins SPTBN1, KHSRP and PYGL are potential biomarkers for prognosis. Our results also show that co-expression networks are able to extrapolate tumor-specific biology as well as biological mechanisms empowering prognostic marker discovery, even with a limited number of samples.

Citation Format: Giulia Mantini, Andrea Valles, Tessa Le Large, Mjriam Capula, Niccola Funel, Thang Pham, Sander Piersma, Geert Kazemier, Maarten Bijlsma, Elisa Giovannetti, Connie Jimenez. Co-expression analysis reveals tumor biology and prognostic biomarkers in pancreatic ductal adenocarcinoma [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr LB-239.

1640 Pulmonary valve in carcinoid disease: be suspicious of functional assessment

Carcinoid heart disease occurs in 50% of patients with carcinoid syndrome, especially on serotonin-secreting neuroendocrine tumors (NET) [1, 2]. Carcinoid heart disease"s typical findings are carcinoid plaques, composed of smooth muscle, myofibroblasts and endothelium. These plaques, most frequently localized on the right side valvular cusps and leaflets, produce fixation and retraction, causing regurgitation and/or stenosis [3, 4, 5]. Left-sided heart disease is rare (<10%), as serotonin is purified in the pulmonary circulation [3, 6, 7].

We present the case of a 67 year old female patient with previous history of right ovarian NET. She presented with dyspnea (II-III NYHA functional class), and slight edema in lower limbs. She denied symptoms of carcinoid syndrome before or after the ovarian surgery.

Examination showed an increased jugular venous pulse.

Transthoracic echocardiography (TTE) showed severely dilated right cavities and a rigid, immobile tricuspid valve, with massive tricuspid regurgitation (Panel A, 1). Anatomy of

pulmonary valve was not properly visualized but jet area of pulmonary regurgitation was small (Panel A, 2). Left cavities and valves were intact.

As TTE was not anatomically conclusive, a cardiac magnetic resonance (CMR) and a cardiac computed tomography (CCT) were performed to assess the carcinoid involvement of pulmonary valve.

CMR showed severely dilated right ventricle with mild impairment of systolic function (Panel A, 3). Based on phase contrast imaging, pulmonary regurgitation fraction was 14%,

suggestive of a mild grade. However, CCT showed a diffuse thickening of the pulmonary valve, with complete opening during diastole (Panel A, 4, arrowhead). Finally, the patient underwent replacement of tricuspid valve and pulmonary valve for biological prosthesis without complications.

Our case is remarkable because it highlights the limitations of the functional assessment of pulmonary regurgitation in the presence of a concomitant massive tricuspid valve regurgitation, since the rapid equalization of pressure between pulmonary artery and right ventricle reduces the expression of pulmonary regurgitation. For these reason, the anatomic assessment of the pulmonary valve is mandatory to stage the involvement of pulmonary valve in carcinoid disease.

Abstract 1640 Figure. Panel A

P845 Deep vein thrombosis, pulmonary embolism and patent foramen ovale: a lethal mix

A 50-year-old woman without remarkable medical history was admitted at the Emergency Department for acute dyspnoea. The patient had been recently submitted to C5-C6 microdiscectomy. She was tachypneic and oxygen saturation was 88%. CT angiography showed bilateral pulmonary embolism (PE) (Figure 1A, yellow arrowheads) with signs of right ventricle overload. Bilateral deep vein thrombosis was also confirmed. The patient was admitted at the Intensive Care Unit, clinically stable. Few hours later, she presented sudden hemodynamic and respiratory deterioration, requiring invasive mechanical ventilation and vasopressors. Due to recent cervical surgery, systemic fibrinolysis was ruled out. Decision for percutaneous thrombectomy and inferior vena cava filter placement was made. Nevertheless, percutaneous thrombectomy was unsuccessful due to the impossibility to catheterize pulmonary artery. Contrast injection demonstrated that the guiding catheter was located in the left atrium (Figure 1B), suggesting a patent foramen ovale (PFO). Transoesophageal echocardiogram confirmed the presence of a 5x6 mm PFO with right-to-left shunt (Figures 1C – yellow arrows, and 1D). In addition, a 4 cm mobile mass attached to the aortic valve and protruding throughout the left ventricle outflow tract was visualized, suggesting paradoxical embolism (Figure 1E – white arrows). Accordingly, open surgical approach with pulmonary thrombectomy, PFO closure and removal of the left-sided thrombus was decided. Unfortunately, despite careful cannulation, thrombus was not found when aortic valve was inspected. Worst suspicions were confirmed, when the patient presented non-reactive mydriatic pupils. A brain CT showed signs of an extensive bihemisferic ischemic stroke (Figure 1F) presumably related to cerebral embolization of aortic thrombus. The patient finally died. Autopsy study was not consented.

PFO has been associated with paradoxical embolisms and risk of stroke in PE. This case strikingly illustrates that treatment of these patients may be challenging in spite of an adequate diagnosis and management.

Abstract P845 Figure.

1095 Effective image-guided medical management in effusive constrictive pericarditis

A 59 year old man was admited to hospitalization for persistent chest pain related to acute pericarditis. Within the admision tests, a transthoracic echography was performed, showing a moderate pericardial effusion with ventricular septal bounce and significant respiratory variations in mitral and tricuspid inflows, all of it consistent with effusive-constrictive pericarditis (Panel A). Anti-inflammatory treatment with ibuprofen and colchicine was started.

During the first 48 hours of admission there was a clinical and hemodinamic worsening in the patient’s condition that forced the performance of a pericardial window, obtaining a very little quantity of dense pericardial fluid. Looking for a more accurate study of the pericardium, a cardiovascular magnetic resonance (CMR) was performed, revealing a thick heterogeneous pericardial effusion (Panel B) and a significant late gadolinium enhancement of both pericardial layers (Panel C). All these findings where consistent with an effusive constrictive pericarditis with persistent inflammatory activity despite high doses of conventional inflammatory treatment. Furthermore, the growth of Propionibacterium acnes in the pericardial fluid disclosed the etiology of this condition.

Medical treatment was enhanced with high doses of intravenous corticosteroid, ceftriaxone and doxycycline. During the following days, the patient showed an excellent response achieving the complete clinical and echocardiographic relief of constrictive signs (Panel D).

Effusive constrictive pericarditis is characterized by the presence of pericardial effusion and constriction secondary to an inflammatory process of the pericardium. Pericardiectomy might be necessary in case of failure of medical treatment, a very common scenario in this kind of .pericarditis.

Our case is remarkable because it demonstrates the value of CMR to detect persistent inflammation of pericardium despite high doses of conventional medical treatment for pericaricarditis guiding the successful escalation to intravenous corticosteroid and avoiding the risk of an unnecessary cardiac surgery.

Abstract 1095 Figure.

Role of boost radiotherapy for local control of pure ductal carcinoma in situ after breast-conserving surgery: a multicenter, retrospective study of 622 patients

PURPOSE

To evaluate the effect of boost radiotherapy on ipsilateral breast tumor recurrence (IBTR) for ductal carcinoma in situ (DCIS) after breast-conserving surgery and whole breast radiotherapy (WBRT) with or without boost.

METHODS AND MATERIALS

Retrospective, multicentre study of 622 patients (624 tumors) diagnosed with pure DCIS from 1993-2011.

RESULTS

Most tumors (377/624; 60.4%) received a boost. At a median follow-up of 8.8 years, IBTR occurred in 64 cases (10.3%). A higher percentage of patients with risk factors for IBTR received a boost (p < 0.05). Boost was not associated with lower rates of IBTR than WBRT alone (HR 0.75, 95% CI 0.42-1.35). On the univariate analyses, IBTR was significantly associated with tumor size (11-20 mm, HR 2.32, 95% CI 1.27-4.24; and > 20 mm, HR 2.10, 95% CI 1.14-3.88), re-excision (HR 1.76, 95% CI 1.04-2.96), and tamoxifen (HR 2.03, 95% CI 1.12-3.70). Boost dose > 16 Gy had a protective effect (HR 0.39, 95% CI 0.187-0.824). Multivariate analyses confirmed the independent associations between IBTR and 11-20 mm (p = 0.02) and > 20 mm (p = 0.009) tumours, and re-excision (p = 0.006). On the margin-stratified multivariate analysis, tamoxifen was a poor prognostic factor in the close/positive margin subgroup (HR 4.28 95% CI 1.23-14.88), while the highest boost dose ( > 16 Gy) had a significant positive effect (HR 0.34, 95% CI 0.13-0.86) in the negative margin subgroup.

CONCLUSIONS

Radiotherapy boost did not improve the risk of IBTR. Boost radiotherapy was more common in patients with high-risk disease. Tumor size and re-excision were significant independent prognostic factors.

Abstract 4010: Identification of signaling pathways involved in colorectal adenoma-to-carcinoma progression using phosphoproteomics

Background Colorectal cancer (CRC) develops in a multi-step-process from normal epithelium, through a pre-malignant lesion (adenoma), into a malignant lesion (adenocarcinoma). A minority of about 5% of adenomas will ultimately progress into cancer. To improve clinical practice it is important to identify the subgroup of colorectal adenomas that is at risk of progressing to cancer. By extensive genomic analysis we have shown that specific copy number alterations are associated with risk of progression. An example of such an alteration is the gain of chromosome arm 20q and we identified AURKA and TPX2 as major drivers of this amplicon. Yet, the activation status of these and other genes during colorectal carcinogenesis and the downstream signaling pathways affected with gene (in)activation are not fully known. In order to better understand the biology of adenoma to carcinoma transition, we performed a comprehensive analysis of phosphoproteomes at different stages of colorectal carcinogenesis.

Methods Phosphotyrosine containing peptides were immunoprecipitated from 5 mg of colorectal adenoma (n=81) and colorectal carcinoma tissues (n=50) using agarose bead-coupled phosphotyrosine antibody P-Tyr-1000. A Q Exactive HF mass spectrometer was used to perform NanoLC-MS/MS. Spectral counts of phosphoproteins and ion intensities of phosphopeptides were defined by MaxQuant for relative quantitation of protein phosphorylation.

Results Phosphotyrosine-based phosphoproteomics of the 131 colorectal tissue samples yielded 6056 phosphopeptides, corresponding to 2745 unique phosphoproteins including 183 phosphokinases. Data analysis to identify regulated phosphorylation states and inference of kinase activity is ongoing.

Conclusions and future plans This is the first large phosphoproteomics dataset of colorectal adenomas and carcinomas. Preliminary data analysis shows promising differences in kinase activities between adenomas and carcinomas. After further analysis, we will manipulate the activity of the driver kinases in adenoma-derived organoids and monitor tumor outgrowth in mice.

Citation Format: Sanne Martens-de Kemp, Alex Henneman, Richard de Goeij-de Haas, Sander Piersma, Thang Pham, Gerrit Meijer, Beatriz Carvalho, Connie Jimenez. Identification of signaling pathways involved in colorectal adenoma-to-carcinoma progression using phosphoproteomics [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 4010.

Next Generation Flow for highly sensitive and standardized detection of minimal residual disease in multiple myeloma

Flow cytometry has become a highly valuable method to monitor minimal residual disease (MRD) and evaluate the depth of complete response (CR) in bone marrow (BM) of multiple myeloma (MM) after therapy. However, current flow-MRD has lower sensitivity than molecular methods and lacks standardization. Here we report on a novel next generation flow (NGF) approach for highly sensitive and standardized MRD detection in MM. An optimized 2-tube 8-color antibody panel was constructed in five cycles of design-evaluation-redesign. In addition, a bulk-lysis procedure was established for acquisition of ⩾10⁷ cells/sample, and novel software tools were constructed for automatic plasma cell gating. Multicenter evaluation of 110 follow-up BM from MM patients in very good partial response (VGPR) or CR showed a higher sensitivity for NGF-MRD vs conventional 8-color flow-MRD -MRD-positive rate of 47 vs 34% (P=0.003)-. Thus, 25% of patients classified as MRD-negative by conventional 8-color flow were MRD-positive by NGF, translating into a significantly longer progression-free survival for MRD-negative vs MRD-positive CR patients by NGF (75% progression-free survival not reached vs 7 months; P=0.02). This study establishes EuroFlow-based NGF as a highly sensitive, fully standardized approach for MRD detection in MM which overcomes the major limitations of conventional flow-MRD methods and is ready for implementation in routine diagnostics.

Abstract P5-17-08: Study of boost radiotherapy's influence on local control in 646 pure ductal carcinoma in situ breast cancer with long-term follow-up

BACKGROUND: Boost radiotherapy (B-RT) improves outcome in patients (pts) with invasive breast cancer. It's use in patients with pure ductal carcinoma in situ (DCIS) is unclear. There are two ongoing randomize trials, results are expected in ten years. Twelve retrospective observational studies have been published since 2006, the recent meta-analysis, support boost in the presence of positive margins.

PATIENTS and METHODS: We analyse a retrospective women's cohort of 646 pure DCIS patients (pts) treated mainly in two Hospitals (n=518) from 1993 to 2014. The other ten Hospitals included 128 pts all 2005 long. Proportions were compared by boost status, using the chi-square tests. The impact of boost radiation on the development of local recurrence (LR) was determined using survival analyses. In the comparison of Kaplan-Meier (K-M) was used log-rank test.

RESULTS: B-RT subgroup is 394 pts (61%), noB-RT 252 (39%). Median follow-up (FU) is 8.8 years. High risk factors: young age, size, margin status and tamoxifen (TMX) show differences among B-RT (p&lt;0.05). 46% were Estrogen Receptor positive (ER+), 30% B-RT and 16% noB-RT. 22% RE+ in B-RT take TMX vs 9.4 % RE+ noB-RT. Total LR 65 (10%). In situ LR 30 pts (4,6%) and Invasive (Inv) 35 (5,4%). By subgroup, LR in B-RT 47 (12%) vs. 18 (7%) in noB-RT. By subtype, In situ LR in B-RT 20 (5.1%) vs. noB-RT 10 (4%). Inv LR in B-RT 27 (6.9%) vs. noB-RT 8 (3.2%). In uni & multivariate analysis, tumour size, Re-Excision, and TMX, are significant LR risk factors (p&lt;0.05). Boost total doses &gt;16 Gy in the B-RT subgroup is a LR significant risk factor related to 10-16 Gy (p∼0.05). TMX and Dose Boost are related (p&lt;0.001). When Dose is introduced in multivariate analysis model, TMX lost signification. Contralateral local recurrence (CLR) in 29 pts (7%). Second tumours 9 pts (NSD between subgroups). Global disease free survival (DFS) is 80.5%, 77% in B-RT vs. 85% in noB-RT. Four pts have a LR combined with CLR; 2 pts have a LR and a second tumor; 1 pt with CLR and second tumour; 1 pt a Inv regional recurrence; 1 pt mixosarcoma in ipsilateral breast and lung metastases. Deaths: 3 pts (0.5%) after an Inv LR; 3 pts (0.5%) after Inv CR; 20 pts other causes; 10 pts lost their FU. Median FU in B-RT subgroup was 9y vs. 8.3y in noB-RT. The maximum FU according LR in B-RT is 20.6y vs. 17.4y in noB-RT. RL is not significant according to Boost (K-M p=0.398). Median LR in situ or inv depending of B-RT vs. noB-RT shows NSD (p=0.663).

CONCLUSIONS: In this large cohort retrospective study with long-term follow-up B-RT was associated with similar LR as noB-RT despite being used more frequently with higher risk disease. Dose boost &gt;16 Gy has a protective effect. Tamoxifen and boost dose are related variables. Further evidence, based on ongoing randomized trials results is essential.

Citation Format: Cambra MJ, Moreno F, Sanz X, Anglada L, Moià M, Reyes V, Arenas M, Pedro A, Ballester R, García V, Sanjosé S, Cusidó M, Jimenez C, Macià M, Solé JM, Farrus B. Study of boost radiotherapy's influence on local control in 646 pure ductal carcinoma in situ breast cancer with long-term follow-up. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P5-17-08.

Effect of long-term prophylaxis in the development of cytomegalovirus-specific T-cell immunity in D+/R- solid organ transplant recipients

BACKGROUND

This study aimed to characterize the dynamics of acquisition of cytomegalovirus (CMV)-specific cell-mediated immunity (CMI) in CMV donor positive/recipient negative solid organ transplant (SOT) patients receiving long-term antiviral prophylaxis, and to determine whether development of CMI confers protection against CMV disease.

METHODS

A prospective multicenter study was conducted in Spain from September 2009 to September 2012. Whole blood specimens were prospectively collected at 30, 90, 120, 200, and 365 days after SOT, and CMI was determined by enumeration of CMV pp65 and IE-1-specific CD69(+) /interferon-γ-producing CD8(+) and CD4(+) T cells by flow cytometry for intracellular cytokine staining. As part of a simultaneous clinical trial, patients received either early prophylaxis (in the first 3 days after transplantation) in the first period of the study or delayed prophylaxis (initiated at day 14) during the second period of the study. The impact of the dynamics of acquisition of CMV-specific CMI on the incidence of CMV disease was evaluated by Kaplan-Meier survival analysis.

RESULTS

A total of 95 SOT recipients were recruited. CMV infection and disease occurred in 38 (40%) and 26 (27.4%) patients, respectively. The proportion of patients achieving any detectable CMV-specific CMI response at each of the different monitoring points was higher in liver transplant recipients, as compared to kidney or heart transplant recipients. The presence of any detectable response at day 120 or 200 was protective against the development of CMV disease (positive predictive values 92% and 93%, respectively).

CONCLUSIONS

The rate of acquisition of CMV-specific CMI in SOT recipients undergoing antiviral prophylaxis differed significantly between different SOT populations. Patients developing any detectable CMI response were protected against the occurrence of CMV disease.

Abstract 1563: Stool proteomics reveals novel candidate biomarkers for colorectal cancer screening

Introduction and objectives: Early detection of colorectal cancer (CRC) and its precursor lesions is an effective approach to reduce CRC mortality rates. The fecal immunochemical test (FIT) is a non-invasive CRC screening test that detects small traces of the blood protein hemoglobin. Although beneficial in its current form, the FIT test characteristics leave room for improvement. The aim of the present study was to identify and validate novel protein biomarkers in stool that complement or outperform the current hemoglobin-based test, to improve its diagnostic accuracy.

Methods: Proteins isolated from stool from 10 subjects without any signs of colorectal neoplasia (controls) at colonoscopy and from 12 CRC patients were analyzed by GeLC-MS/MS (discovery set). Data were analyzed by comparing protein abundancies, measured as spectral counts. Analysis of differential proteins was performed using the beta-binomial test. Findings were validated by mass spectrometry (Q-Exactive) in an independent series of 292 stool samples obtained from control subjects (n = 109) and subjects with adenomas (n = 55), advanced adenomas (n = 53), or CRCs (n = 75).

Results and Discussion: In total 830 human proteins were identified in the discovery set, of which 134 were significantly enriched in CRC. These included 78 proteins that were significantly more enriched in FIT-negative CRC stool samples compared to controls. Preliminary analysis of the validation set indicates that more than half of these markers are significantly more abundant in CRC samples compared to controls.

Conclusion: Proteome profiling of stool samples revealed novel candidate biomarkers to improve current CRC screening tests. More data analysis is currently ongoing to select most promising protein biomarkers for clinical assay development.

Citation Format: Linda JW Bosch, Meike de Wit, Annemieke C. Hiemstra, Sander Piersma, Thang Pham, Gideon Oudgenoeg, George Scheffer, Sandra Mongera, Malgorzata Komor, Jochim Terhaar Sive Droste, Frank A. Oort, Sietze van Turenhout, Ilhame Ben Larbi, Chris JJ Mulder, Beatriz Carvalho, Remond JA Fijneman, Connie Jimenez, Gerrit A. Meijer. Stool proteomics reveals novel candidate biomarkers for colorectal cancer screening. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 1563. doi:10.1158/1538-7445.AM2015-1563

Effect of delaying prophylaxis against CMV in D+/R- solid organ transplant recipients in the development of CMV-specific cellular immunity and occurrence of late CMV disease

OBJECTIVES

Evaluate the protective effect against late CMV disease of delaying antiviral prophylaxis initiation in D+/R- patients receiving solid organ transplant (SOT).

METHODS

Prospective multicenter study in D+/R- SOT recipients in Spain (Sept/09-Sept/12). Whole blood specimens were prospectively collected after Tx for CMV-specific cell-mediated immunity (CMI) determination. Two prophylaxis strategies were compared: early prophylaxis (EP; starting within the first 3 days after Tx) and delayed prophylaxis (DP; starting 14 days after Tx). Risk factors for the occurrence of CMV disease were determined by survival analysis and proportional risk Cox regression models.

RESULTS

We included 95 patients (50 EP V 45 DP). Twenty six patients (27.4%) developed CMV disease: 32.7% EP vs. 20% DP; (p = 0.2). No cases of CMV disease were reported previously to beginning delayed prophylaxis. The percentage of individuals with detectable CMI response was higher in patients with DP although differences did not reach statistic significance (42% vs 29.6% at day 200 after Tx; p = 0.4). There was a clear trend towards less end-organ CMV disease in patients receiving DP (18.2% EP vs 5% DP; p = 0.09) and DP was the only protective factor in the multivariate analysis (HR: 0.26; CI: 0.05-1.2; p = 0.09).

CONCLUSIONS

A 14-day delay in CMV prophylaxis in D+/R- SOT recipients is safe and may reduce the incidence of late CMV end-organ disease although correlation of this effect with CMI responses was not complete.

Treatment Planning for Image-Guided Neuro-Vascular Interventions Using Patient-Specific 3D Printed Phantoms

Minimally invasive endovascular image-guided interventions (EIGIs) are the preferred procedures for treatment of a wide range of vascular disorders. Despite benefits including reduced trauma and recovery time, EIGIs have their own challenges. Remote catheter actuation and challenging anatomical morphology may lead to erroneous endovascular device selections, delays or even complications such as vessel injury. EIGI planning using 3D phantoms would allow interventionists to become familiarized with the patient vessel anatomy by first performing the planned treatment on a phantom under standard operating protocols. In this study the optimal workflow to obtain such phantoms from 3D data for interventionist to practice on prior to an actual procedure was investigated. Patient-specific phantoms and phantoms presenting a wide range of challenging geometries were created. Computed Tomographic Angiography (CTA) data was uploaded into a Vitrea 3D station which allows segmentation and resulting stereo-lithographic files to be exported. The files were uploaded using processing software where preloaded vessel structures were included to create a closed-flow vasculature having structural support. The final file was printed, cleaned, connected to a flow loop and placed in an angiographic room for EIGI practice. Various Circle of Willis and cardiac arterial geometries were used. The phantoms were tested for ischemic stroke treatment, distal catheter navigation, aneurysm stenting and cardiac imaging under angiographic guidance. This method should allow for adjustments to treatment plans to be made before the patient is actually in the procedure room and enabling reduced risk of peri-operative complications or delays.

Abstract 3773: Intestinal glutathione peroxidase (GPx2) promotes differentiation of colorectal cancer stem cells by modulating the rate of protein synthesis

Primary colorectal tumors and liver metastases can be established in vitro as colonosphere cultures. These 3D cultures are enriched in cancer stem cells (CSCs) and create phenocopies of the original patient tumor upon transplantation into mice. We have performed proteomics analysis of a series of colonosphere cultures and show high expression of the Wnt-target gene intestinal glutathione peroxidase (GPx2). GPx2 is a member of the GPx family of ROS scavenging enzymes but its function in colorectal cancer is not known. Excess oxidative damage in normal and cancer stem cell (SC) populations can lead to (C)SC exhaustion. Therefore, we tested whether GPx2 may play a role in colorectal CSC maintenance. We found that GPx2 is predominantly expressed by differentiated tumor cells in human colorectal tumors. A construct in which the GPx2-promoter drives GFP expression revealed that GPx2high cells express differentiation markers and proliferate rapidly, while GPx2low cells express stem cell markers (Oct4, Nanog, Sox2, OLFM4) and proliferate slowly. To study the function of GPX2 in CSC maintenance we generated GPx2 knockdown (kd) cultures. Depletion of GPX2 greatly increased the fraction of immature CSCs and inhibited cellular differentiation. GPx2-kd cells formed slowly growing tumors with high CSC content, while GPx2 overexpression resulted in the formation of rapidly proliferating well-differentiated tumors with low CSC content. Gene Set Enrichment Analysis (GSEA) using gene expression profiles of two independent series of colorectal tumors showed that GPx2 expression was inversely correlated with published gene signatures for immature cells (Nanog, Oct4 and Sox2 target genes) and for cell proliferation. Low expression of GPx2 also correlated with poor patient survival. To explore how GPX2 affects CSC maintenance we performed gene ontology analyses and found that GPx2 expression is most strongly correlated with genes governing protein synthesis. GPx2 knockdown resulted in strongly reduced ribosomal gene expression and reduced protein synthesis. Strikingly, chronic cycloheximide-mediated suppression of protein synthesis in colonosphere cultures also increased the pool of slow-cycling CSCs, similar to GPx2 knockdown. Taken together, our results identify the rate of protein synthesis as a critical new determinant of the CSC phenotype. By stimulating protein synthesis GPx2 drives the differentiation, proliferation and exhaustion of colorectal CSCs. Complete elucidation of this pathway may identify targets for differentiation-stimulating anti-cancer therapy.

Citation Format: Benjamin Emmink, Jamila Laoukili, Anna Kipp, Klaas Govaert, Szabolcs Fatrai, Andre Verheem, Regina Brigelius-Flohe, Connie Jimenez, Inne Borel Rinkes, Onno Kranenburg. Intestinal glutathione peroxidase (GPx2) promotes differentiation of colorectal cancer stem cells by modulating the rate of protein synthesis. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 3773. doi:10.1158/1538-7445.AM2013-3773

A form of apolipoprotein a-I is found specifically in relapses of focal segmental glomerulosclerosis following transplantation

Recurrence of idiopathic focal segmental glomerulosclerosis (FSGS) following kidney transplantation occurs in a large percentage of patients. Accurate prediction of recurrence and elucidation of its pathogenesis are major therapeutic goals. To detect differential proteins related to FSGS recurrence, proteomic analysis was performed on plasma and urine samples from 35 transplanted idiopathic FSGS patients, divided into relapsing and nonrelapsing. Several proteins were detected increased in urine of relapsing FSGS patients, including a high molecular weight form of apolipoprotein A-I, named ApoA-Ib, found exclusively in relapsing patients. This finding was verified by Western blot individually in the 35 patients and validated in an independent group of 40 patients with relapsing or nonrelapsing FSGS, plus two additional groups: FSGS-unrelated patients showing different proteinuria levels (n = 30), and familial FSGS transplanted patients (n = 14). In the total of 119 patients studied, the ApoA-Ib form was detected in 13 of the 14 relapsing FSGS patients, and in one of the 61 nonrelapsing patients. Only one of the 30 patients with FSGS-unrelated proteinuria tested positive for ApoA-Ib, and was not detected in familial patients. Urinary ApoA-Ib is associated with relapses in idiopathic FSGS and warrants additional investigation to determine its usefulness as biomarker of relapse following transplantation.