First Experience Using 18F-Flubrobenguane PET Imaging in Patients with Suspected Pheochromocytoma or Paraganglioma.

Pheochromocytomas and paragangliomas are a rare tumor entity originating from adrenomedullary chromaffin cells in the adrenal medulla or in sympathetic, paravertebral ganglia outside the medulla. Small lesions are especially difficult to detect by conventional CT or MRI and even by SPECT with the currently available radiotracers (e.g., metaiodobenzylguanidine [MIBG]). The novel PET radiotracer 18F-flubrobenguane could change the diagnostic paradigm in suspected pheochromocytomas and paragangliomas because of its homology with MIBG and the general advantages of PET imaging. The aim of this retrospective analysis was to evaluate 18F-flubrobenguane in pheochromocytomas and paragangliomas and to investigate the biodistribution in patients. Methods: Twenty-three patients with suspected pheochromocytoma or paraganglioma underwent PET/CT or PET/MRI at 63 ± 24 min after injection of 256 ± 33 MBq of 18F-flubrobenguane. The SUVmean and SUVmax of organs were measured with spheric volumes of interest. Threshold-segmented volumes of interest were used to measure the SUVmean or SUVmax of the tumor lesions. One reader evaluated all cross-sectional imaging datasets (CT or MRI) separately, as well as the PET hybrid datasets, and reported the lesion number and size. The diagnostic certainty for a positive lesion was scored on a 3-point scale. Results:18F-flubrobenguane showed a reproducible, stable biodistribution, with the highest SUVmax and SUVmean being in the thyroid gland (30.3 ± 2.2 and 22.5 ± 1.6, respectively), pancreas (12.2 ± 0.8 and 9.5 ± 0.7, respectively), and tumor lesions (16.8 ± 1.7 and 10.1 ± 1.1, respectively) and the lowest SUVmax and SUVmean being in muscle (1.1 ± 0.06 and 0.7 ± 0.04, respectively) and the lung (2.5 ± 0.17 and 1.85 ± 0.13, respectively). In a subgroup analysis, a significantly higher average SUVmean was seen for both pheochromocytoma and paraganglioma than for healthy adrenal glands (11.9 ± 2.0 vs. 9.9 ± 1.5 vs. 3.7 ± 0.2, respectively). In total, 47 lesions were detected. The reader reported more and smaller lesions with higher certainty in PET hybrid imaging than in conventional imaging; however, statistical significance was not reached. Of the 23 (23/47, 49%) lesions smaller than 1 cm, 61% (14/23) were found on hybrid imaging only. Conclusion: Our preliminary data suggest 18F-flubrobenguane PET to be a new, effective staging tool for patients with suspected pheochromocytoma or paraganglioma. Major advantages are the fast acquisition and high spatial resolution of PET imaging and the intense uptake in tumor lesions, facilitating detection. Further studies are warranted to define the role of 18F-flubrobenguane PET, particularly in comparison to standard diagnostic procedures such as MRI or 123I-MIBG SPECT/CT.

Regulation of Epithelial Plasticity Determines Metastatic Organotropism in Pancreatic Cancer.

The regulation of metastatic organotropism in pancreatic ductal a denocarcinoma (PDAC) remains poorly understood. We demonstrate, using multiple mouse models, that liver and lung metastatic organotropism is dependent upon p120catenin (p120ctn)-mediated epithelial identity. Mono-allelic p120ctn loss accelerates KrasG12D-driven pancreatic cancer formation and liver metastasis. Importantly, one p120ctn allele is sufficient for E-CADHERIN-mediated cell adhesion. By contrast, cells with bi-allelic p120ctn loss demonstrate marked lung organotropism; however, rescue with p120ctn isoform 1A restores liver metastasis. In a p120ctn-independent PDAC model, mosaic loss of E-CADHERIN expression reveals selective pressure for E-CADHERIN-positive liver metastasis and E-CADHERIN-negative lung metastasis. Furthermore, human PDAC and liver metastases support the premise that liver metastases exhibit predominantly epithelial characteristics. RNA-seq demonstrates differential induction of pathways associated with metastasis and epithelial-to-mesenchymal transition in p120ctn-deficient versus p120ctn-wild-type cells. Taken together, P120CTN and E-CADHERIN mediated epithelial plasticity is an addition to the conceptual framework underlying metastatic organotropism in pancreatic cancer.

Introducing a novel highly prognostic grading scheme based on tumour budding and cell nest size for squamous cell carcinoma of the uterine cervix.

A novel histopathological grading system based on tumour budding and cell nest size has recently been shown to outperform conventional (WHO-based) grading algorithms in several tumour entities such as lung, oral, and oesophageal squamous cell carcinoma (SCC) in terms of prognostic patient stratification. Here, we tested the prognostic value of this innovative grading approach in two completely independent cohorts of SCC of the uterine cervix. To improve morphology-based grading, we investigated tumour budding activity and cell nest size as well as several other histomorphological factors (e.g., keratinization, nuclear size, mitotic activity) in a test cohort (n = 125) and an independent validation cohort (n = 122) of cervical SCC. All parameters were correlated with clinicopathological factors and patient outcome. Small cell nest size and high tumour budding activity were strongly associated with a dismal patient prognosis (p < 0.001 for overall survival [OS], disease-specific survival, and disease-free survival; test cohort) in both cohorts of cervical SCC. A novel grading algorithm combining these two parameters proved to be a highly effective, stage-independent prognosticator in both cohorts (OS: p < 0.001, test cohort; p = 0.001, validation cohort). In the test cohort, multivariate statistical analysis of the novel grade revealed that the hazard ratio (HR) for OS was 2.3 for G2 and 5.1 for G3 tumours compared to G1 neoplasms (p = 0.010). In the validation cohort, HR for OS was 3.0 for G2 and 7.2 for G3 tumours (p = 0.012). In conclusion, our novel grading algorithm incorporating cell nest size and tumour budding allows strongly prognostic histopathological grading of cervical SCC superior to WHO-based grading. Therefore, our data can be regarded as a cross-organ validation of previous results demonstrated for oesophageal, lung, and oral SCC. We suggest this grading algorithm as an additional morphology-based parameter for the routine diagnostic assessment of this tumour entity.

68Ga-PSMA-HBED-CC Uptake in Cervical, Celiac, and Sacral Ganglia as an Important Pitfall in Prostate Cancer PET Imaging.

The study aims to investigate the presence of physiologic prostate-specific membrane antigen (68Ga-PSMA)-ligand uptake on PET in cervical, celiac, and sacral ganglia of the sympathetic trunk as a pitfall for lymph node metastases in prostate cancer imaging. Methods: Four hundred seven patients who underwent Glu-NH-CO-NH-Lys radiolabeled with 68Ga-gallium N,N-bis[2-hydroxy-5-(carboxyethyl)benzyl]ethylenediamine-N,N-diacetic acid (68Ga-PSMA-HBED-CC) PET (combined with a diagnostic CT) were retrospectively analyzed. The number of 68Ga-PSMA PET-positive cervical, celiac, and sacral ganglia was determined, and the configuration and SUVmax of each ganglion were measured. In addition, the configuration and SUVmax of adjacent lymph node metastases in the respective region (cervical, celiac, or sacral) were determined. Results:68Ga-PSMA-ligand uptake above background was detected in 401 (98.5%) patients in any peripheral ganglia, in 369 (92%) patients in cervical ganglia, in 363 (89%) patients in celiac ganglia, and in 183 (46%) patients in sacral ganglia. The 68Ga-PSMA-ligand uptake was highest in celiac (mean SUVmax, 2.9 ± 0.8 vs. cervical mean SUVmax, 2.4 ± 0.6) and sacral (mean SUVmax 1.7 ± 0.5; both P < 0.0001) ganglia. Intraindividually there was a statistically significant but weak to moderate correlation between the 68Ga-PSMA-ligand uptake in cervical versus celiac ganglia (R = 0.34, P < 0.0001), cervical versus sacral (R = 0.52, P < 0.0001), and celiac versus sacral (R = 0.16, P < 0.05). The 68Ga-PSMA-ligand uptake was significantly more intense in adjacent lymph node metastases than the respective ganglia (cervical: 18.0 ± 16.2 vs. 2.4 ± 0.6, P < 0.0001; celiac: 13.5 ± 12.3 vs. 2.9 ± 0.8, P < 0.0001; sacral: 13.4 ± 11.6 vs. 1.7 ± 0.5, P < 0.0001). Furthermore, ganglia predominantly exhibit a band-shaped configuration (71.2%), followed by a teardrop (26.8%) and only rarely a nodular configuration (2.0%). Conversely, lymph node metastases are only rarely band-shaped (1.1%), but more often show teardrop (40.3%) or nodular appearance (58.6%) (P < 0.00001). Conclusion:68Ga-PSMA-ligand uptake in ganglia along the sympathetic trunk as assessed by 68Ga-PSMA-HBED-CC PET represents an important pitfall in prostate cancer PET imaging. The 68Ga-PSMA-ligand uptake is higher in celiac ganglia than cervical or sacral ganglia, and the level of 68Ga-PSMA-ligand uptake seems to be patient-related. For the differentiation between lymph node metastases and sympathetic ganglia, both intensity of 68Ga-PSMA-ligand uptake and exact localization and configuration of the respective lesion should be examined carefully.

A Novel Grading System Based on Tumor Budding and Cell Nest Size Is a Strong Predictor of Patient Outcome in Esophageal Squamous Cell Carcinoma.

The determination of prognosis in patients with esophageal squamous cell carcinoma (ESCC) is primarily based on staging according to the TNM-classification, whereas conventional grading is of minor clinical importance because of its deficiencies in prognostic patient stratification. Recently, a novel, highly prognostic grading scheme based on budding activity and cell nest size has been proposed for squamous cell carcinoma (SCC) of both pulmonary as well as oral origin. In order to investigate the utility and transferability of this approach to ESCC, we evaluated budding activity and cell nest size, as well as other histomorphologic characteristics, in a cohort of 135 primarily resected tumors and correlated the results with clinicopathologic and outcome parameters. High budding activity and small cell nest size showed a strong association with reduced overall, disease-specific, and disease-free survival (P<0.001, respectively) in ESCC. The combination of both markers in a 3-step grading system showed excellent prognostic separation of well-differentiated (G1), moderately differentiated (G2), and poorly differentiated (G3) carcinomas (P<0.001). The hazard ratio for disease-free survival in multivariate analysis under inclusion of stage was 2.97 for G2 and 5.42 for G3 ESCC (P<0.001). World Health Organization-based grading had no prognostic impact. Taken together, our data prove the value of tumor budding and cell nest size as excellent outcome predictors in ESCC and validate the utility of a previously established grading scheme proposed for oral and pulmonary SCC in this tumor entity. Ultimately, these combined efforts may result in a universal grading system for SCC regardless of the site of origin.

Multiparametric 18F-FDG PET/MR follow-up in a patient with autoimmune pancreatitis.

BACKGROUND: Positron emission tomography/magnetic resonance imaging (PET/MR) is a new multimodal imaging technique, which might improve the diagnostic performance not only in oncological patients but also in patients with non-neoplastic inflammatory lesions as routinely used 18F-FDG is not a cancer specific agent. CASE PRESENTATION: Multiparametric 18F-FDG PET/MR in a woman with pain in the upper abdomen and inconclusive laboratory and clinical data presenting with moderately increased, diffuse 18F-FDG uptake with delayed contrast enhancement, diffusion-restriction and focal enlargement in the pancreatic body being suggestive for autoimmune pancreatitis (AIP). Follow-up 18F-FDG PET/MR after initiation of steroid therapy confirmed complete resolution of imaging abnormalities. CONCLUSION: 18F-FDG PET/MR might be valuable in the management of AIP providing complementary data regarding accurate diagnosis and monitoring therapy response to avoid unnecessary surgery.

Loss of Chromosome 18 in Neuroendocrine Tumors of the Small Intestine: The Enigma Remains.

BACKGROUND/AIMS: Neuroendocrine tumors of the small intestine (SI-NETs) exhibit an increasing incidence and high mortality rate. Until now, no fundamental molecular event has been linked to the tumorigenesis and progression of these tumors. Only the loss of chromosome 18 (Chr18) has been shown in up to two thirds of SI-NETs, whereby the significance of this alteration is still not understood. We therefore performed the first comprehensive study to identify Chr18-related events at the genetic, epigenetic and gene/protein expression levels. METHODS: We did expression analysis of all seven putative Chr18-related tumor suppressors by quantitative real-time PCR (qRT-PCR), Western blot and immunohistochemistry. Next-generation exome sequencing and SNP array analysis were performed with five SI-NETs with (partial) loss of Chr18. Finally, we analyzed all microRNAs (miRNAs) located on Chr18 by qRT-PCR, comparing Chr18+/- and Chr18+/+ SI-NETs. RESULTS: Only DCC (deleted in colorectal cancer) revealed loss of/greatly reduced expression in 6/21 cases (29%). No relevant loss of SMAD2, SMAD4, elongin A3 and CABLES was detected. PMAIP1 and maspin were absent at the protein level. Next-generation sequencing did not reveal relevant recurrent somatic mutations on Chr18 either in an exploratory cohort of five SI-NETs, or in a validation cohort (n = 30). SNP array analysis showed no additional losses. The quantitative analysis of all 27 Chr18-related miRNAs revealed no difference in expression between Chr18+/- and Chr18+/+ SI-NETs. CONCLUSION: DCC seems to be the only Chr18-related tumor suppressor affected by the monoallelic loss of Chr18 resulting in a loss of DCC protein expression in one third of SI-NETs. No additional genetic or epigenetic alterations were present on Chr18.

RSUME is implicated in tumorigenesis and metastasis of pancreatic neuroendocrine tumors.

The factors triggering pancreatic neuroendocrine tumor (PanNET) progression are largely unknown. Here we investigated the role and mechanisms of the sumoylation enhancing protein RSUME in PanNET tumorigenesis. Immunohistochemical studies showed that RSUME is strongly expressed in normal human pancreas, in particular in ß-cells. RSUME expression is reduced in insulinomas and is nearly absent in other types of PanNETs suggesting a role in PanNET tumorigenesis. In human pancreatic neuroendocrine BON1 cells, RSUME stimulates hypoxia-inducible factor-1α (HIF-1α) and vascular endothelial growth factor-A (VEGF-A), which are key components of tumor neovascularisation. In contrast, RSUME suppresses nuclear factor-κB (NF-κB) and its target interleukin-8 (IL-8). Correspondingly, PanNET cells with RSUME knockdown showed decreased HIF-1α activity and increased NF-κB and IL-8 production leading to a moderate reduction of VEGF-A release as reduced HIF-1α/VEGF-A production is partly compensated by NF-κB/IL-8-induced VEGF-A. Notably, RSUME stabilizes the tumor suppressor PTEN, which is frequently lost in PanNETs and whose absence is associated with metastasis formation. In vivo orthotopic transplantation of PanNET cells with or without RSUME expression into nude mice showed that PanNETs without RSUME have reduced PTEN expression, grow faster and form multiple liver metastases. In sum, RSUME differentially regulates key components of PanNET formation suggesting that the observed loss of RSUME in advanced PanNETs is critically involved in PanNET tumorigenesis, particularly in metastasis formation.

Loss of Periostin Results in Impaired Regeneration and Pancreatic Atrophy after Cerulein-Induced Pancreatitis.

The extracellular matrix molecule periostin (POSTN, encoded by POSTN), which is secreted by activated pancreatic stellate cells, has important functions in chronic pancreatitis and pancreatic cancer. However, the role of POSTN in acute pancreatitis and subsequent regeneration processes has not been addressed so far. We analyzed the function of POSTN in pancreatic exocrine regeneration after the induction of a severe acute pancreatitis. Postn-deficient mice and wild-type control animals received repetitive cerulein injections, and a detailed histologic analysis of pancreatic tissues was performed. Although there was no difference in pancreatitis severity in the acute inflammatory phase, the recovery of the exocrine pancreas was massively impaired in Postn-deficient mice. Loss of Postn expression was accompanied by strong pancreatic atrophy and acinar-to-adipocyte differentiation, which was also reflected in gene expression patterns. Our data suggest that POSTN is a crucial factor for proper exocrine lineage-specific regeneration after severe acute pancreatitis.

Resectability After First-Line FOLFIRINOX in Initially Unresectable Locally Advanced Pancreatic Cancer: A Single-Center Experience.

BACKGROUND: FOLFIRINOX is an active but relatively toxic chemotherapeutic regimen for patients with metastatic pancreatic ductal adenocarcinoma (PDAC). The increased frequency of responding tumors shift interest to neoadjuvant approaches. We report our institutional experience with FOLFIRINOX for therapy-naïve patients with locally advanced and initially unresectable PDAC. METHODS: All patients with unresectable locally advanced PDAC who underwent treatment with FOLFIRINOX at a single center between 2011 and 2014 were identified and evaluated retrospectively regarding chemotherapy response, toxicity, conversion to resectability, and survival. Resectability, response to chemotherapy, and postoperative complications were reported according to NCCN-guidelines, RECIST-criteria, and Clavien-Dindo-classification, respectively. RESULTS: Overall, 14 patients received FOLFIRINOX as first-line therapy for locally advanced and unresectable PDAC. Fifty-seven percent of the patients had severe tumor-related comorbidities at the time of diagnosis, and in 86 %, dose reduction due to toxicity was necessary during a median of seven cycles. Nevertheless, only one patient had progressive disease during FOLFIRINOX, whereas the others experienced stable disease (n = 6) or partial remission (n = 6; no restaging in one patient). Oncological tumor resection was possible in 4 patients (29 % of all patients) with no postoperative mortality and only one grade 2 surgical complication. After a median follow-up of 10 months, 4 of the 14 patients were still in remission, 5 were alive with stable disease under ongoing systemic chemotherapy, and 5 died tumor-related. CONCLUSIONS: FOLFIRINOX is a powerful first-line regimen that leads to resectability in a substantial portion of patients with initially unresectable pancreatic cancer.

How fibrosis influences imaging and surgical decisions in pancreatic cancer.

Our understanding of pancreatic ductal adenocarcinoma (PDAC) is shifting away from a disease of malignant ductal cells-only, toward a complex system where tumor evolution is a result of interaction of cancer cells with their microenvironment. This change has led to intensification of research focusing on the fibrotic stroma of PDAC. Pancreatic stellate cells (PSCs) are the main fibroblastic cells of the pancreas which are responsible for producing the desmoplasia in chronic pancreatitis (CP) and PDAC. Clinically, the effect of desmoplasia is two-sided; on the negative side it is a hurdle in the diagnosis of PDAC because the fibrosis in cancer resembles that of CP. It is also believed that PSCs and pancreatic fibrosis are partially responsible for the therapy resistance in pancreatic cancer. On the positive side, a fibrotic pancreas is safer to operate on compared to a fatty and soft pancreas which is prone for postoperative pancreatic fistula. In this review the impact of pancreatic fibrosis on diagnosis of pancreatic cancer and surgical decisions are discussed from a clinical point of view.

MondoA is highly overexpressed in acute lymphoblastic leukemia cells and modulates their metabolism, differentiation and survival.

Acute lymphoblastic leukemia (ALL) is the most common childhood cancer. To identify novel candidates for targeted therapy, we performed a comprehensive transcriptome analysis identifying MondoA (MLXIP) - a transcription factor regulating glycolysis - to be overexpressed in ALL compared to normal tissues. Using microarray-profiling, gene-set enrichment analysis, RNA interference and functional assays we show that MondoA overexpression increases glucose catabolism and maintains a more immature phenotype, which is associated with enhanced survival and clonogenicity of leukemia cells. These data point to an important contribution of MondoA to leukemia aggressiveness and make MondoA a potential candidate for targeted treatment of ALL.

NMD: RNA biology meets human genetic medicine.

NMD (nonsense-mediated mRNA decay) belongs to the best-studied mRNA surveillance systems of the cell, limiting the synthesis of truncated and potentially harmful proteins on the one hand and playing an initially unexpected role in the regulation of global gene expression on the other hand. In the present review, we briefly discuss the factors involved in NMD, the different models proposed for the recognition of PTCs (premature termination codons), the diverse physiological roles of NMD, the involvement of this surveillance pathway in disease and the current strategies for medical treatment of PTC-related diseases.