The clean energy aspect of plastic waste - hydrogen gas production, CO2 reforming, and plastic waste management coincide with catalytic pyrolysis - an extensive review

Clean hydrogen has future fuel capable of receiving an abundance of carbon-neutral energy from hydrogen. In the recent world, new hydrogen affirmation projects have been launched for a green environment. On another side, plastic waste and CO2 threaten the green environment. Vacuum in plastic waste management, plastic waste leads to exhibiting harmful chemicals to the environment. The growth rate of the CO2 concentration in air is 2.45 ppm per year, steadily increasing in 2022. It is realized that uneven climate change, temperature raising the global level, ocean mean level raising, and frequent acidification are dangerous to living and ecosystems. This review discussed tackling multiple harmful environmental fatly by pyrolysis techniques; catalytic pyrolysis is almost reaching the commercialization stage. Recent pyrolysis upgradation methods with hydrogen gas production and the continuous development and execution of sustainable solutions for plastic waste management and CO2 reforming are discussed. Production of carbon nanotubes by plastic waste, the importance of catalyst modification, and the effect of catalyst deactivation are discussed. From this study, integrating the different applications with catalytic modification creates room for multipurpose pyrolysis, CO2 reforming, and hydrogen gas production by pyrolysis techniques capable of giving a sustainable solution for climate change issues and a clean environment. Additionally, carbon utilization by way of carbon nanotube production is also done. Overall, the review supports achieving clean energy from plastic waste.

Targeted Genomic Profiling and Chemotherapy Outcomes in Grade 3 Gastro-Entero-Pancreatic Neuroendocrine Tumors (G3 GEP-NET)

BACKGROUND

Grade 3 gastro-entero-pancreatic neuroendocrine tumors (G3 GEP-NET) are poorly characterized in terms of molecular features and response to treatments.

METHODS

Patients with G3 GEP-NET were included if they received capecitabine and temozolomide (CAPTEM) or oxaliplatin with either 5-fluorouracile (FOLFOX) or capecitabine (XELOX) as first-line treatment (chemotherapy cohort). G3 NET which successfully undergone next-generation sequencing (NGS) were included in the NGS cohort.

RESULTS

In total, 49 patients were included in the chemotherapy cohort: 15 received CAPTEM and 34 received FOLFOX/XELOX. Objective response rate (ORR), progression-free survival (PFS), and overall survival (OS) were 42.9%, 9.0 months, and 33.6 months, respectively. Calculating a Ki67 cutoff using ROC curve analysis, tumors with Ki67 ≥ 40% had lower ORR (51.2% vs. 0%; p = 0.007) and shorter PFS (10.6 months vs. 4.4 months; p < 0.001) and OS (49.4 months vs. 10.0 months; p = 0.023). In patients who received FOLFOX/XELOX as a first-line treatment, ORR, PFS, and OS were 38.2%, 7.9 months, and 30.0 months, respectively. In the NGS cohort (N = 13), the most mutated genes were DAXX/ATRX (N = 5, 38%), MEN1 (N = 4, 31%), TP53 (N = 4, 31%), AKT1 (N = 2, 15%), and PIK3CA (N = 1, 8%).

CONCLUSIONS

FOLFOX/XELOX chemotherapy is active as the first-line treatment of patients with G3 GEP-NET. The mutational landscape of G3 NET is more similar to well-differentiated NETs than NECs.

Diagnostic performance of PET/CT in the detection of liver metastases in well-differentiated NETs

BACKGROUND

The aim of this retrospective study was to compare the diagnostic accuracy of somatostatin receptor (SSR)-PET/CT to liver MRI as reference standard in the evaluation of hepatic involvement in neuroendocrine tumors (NET).

METHODS

An institutional database was screened for "SSR" imaging studies between 2006 and 2021. 1000 NET Patients (grade 1/2) with 2383 SSR-PET/CT studies and matching liver MRI in an interval of +3 months were identified. Medical reports of SSR-PET/CT and MRI were retrospectively evaluated regarding hepatic involvement and either confirmed by both or observed in MRI but not in SSR-PET/CT (false-negative) or in SSR-PET but not in MRI (false-positive).

RESULTS

Metastatic hepatic involvement was reported in 1650 (69.2%) of the total 2383 SSR-PET/CT imaging studies, whereas MRI detected hepatic involvement in 1685 (70.7%) cases. There were 51 (2.1%) false-negative and 16 (0.7%) false-positive cases. In case of discrepant reports, MRI and PET/CT were reviewed side by side for consensus reading. SSR-PET/CT demonstrated a sensitivity of 97.0% (95%CI: 96.0%, 97.7%), a specificity of 97.7% (95%CI: 96.3%, 98.7%), a PPV of 99.0% (95%CI: 98.4%, 99.4%) and NPV of 93.0% (95%CI: 91.0, 94.8%) in identifying hepatic involvement. The most frequent reason for false-negative results was the small size of lesions with the majority < 0.6 cm.

CONCLUSION

This study confirms the high diagnostic accuracy of SSR-PET/CT in the detection of hepatic involvement in NET patients based on a patient-based analysis of metastatic hepatic involvement with a high sensitivity and specificity using liver MRI imaging as reference standard. However, one should be aware of possible pitfalls when a single imaging method is used in evaluating neuroendocrine liver metastases in patients.

Outcome of carcinoid heart syndrome in patients enrolled in the SwissNet cohort

BACKGROUND

Carcinoid heart disease is a rare disease which develops in patients with functional neuroendocrine tumors in an advanced tumor state. Patients diagnosed with carcinoid heart disease have a poor longtime prognosis with respect to morbidity and mortality and long-term data on patient outcomes are lacking.

METHODS AND RESULTS

In this retrospective study, we analyzed outcomes of 23 patients with carcinoid heart disease enrolled into the SwissNet database. We observed that early diagnosis with echocardiographic surveillance of carcinoid heart disease during the course of the neuroendocrine tumor disease was beneficial to overall survival of patients.

CONCLUSION

Through nationwide patient enrollment, the SwissNet registry is a powerful data tool to identify, follow-up and evaluate long-term patient outcomes in patients with rare neuroendocrine tumor driven pathologies including carcinoid heart syndrome with observational methods enabling better therapy optimization to improve patient`s long-term perspectives and survival. In line with the current ESMO recommendations, our data proposes that heart echocardiography should be included as part of the general physical assessment in patients with newly diagnosed NET.

A Case of Cushing's Syndrome from Well-Differentiated Neuroendocrine Tumors of the Small Bowel and Its Mesentery

Adrenocorticotropic (ACTH)-producing neuroendocrine tumours (NETs) are rarely found in the small bowel, and primary mesenteric NETs have only been reported in a few cases globally. We report the case of a 68-year-old female with ectopic Cushing's syndrome due to excessive ACTH secretion from small bowel primary lesions and mesenteric metastasis. Initially, only the mesenteric mass was detected on imaging and endoscopy/colonoscopy, and it was only with surgical exploration that the small bowel lesions were found. This highlights the importance of high clinical suspicion and robust investigation when locating NETs. Surgical resection of the affected small bowel and mesentery was the definitive treatment for this patient. Initial hydrocortisone replacement therapy was needed, and subsequent biochemical tests and clinical reviews demonstrated no recurrence.

Belgian guidelines for pathology reporting of neuroendocrine neoplasms of the pancreaticobiliary and gastrointestinal tract

Since neuroendocrine neoplasms are rare tumors, registration of patient data in national and multinational registries is recommended. Indeed, this will facilitate multicenter studies on the epidemiology, efficacy and safety of diagnostic and therapeutic strategies for well-differentiated neuroendocrine tumors as well as for neuroendocrine carcinomas. In Belgium, data on patient and tumor characteristics of all newly diagnosed malignancies have been collected in the Belgian Cancer Registry since 2004 including anonymized full pathological reports. The Digestive Neuroendocrine Tumor (DNET) registry collects information on classification, staging, diagnostic tools and treatment in a prospective national online database. However, the terminology, classification and staging systems of neuroendocrine neoplasms have changed repeatedly over the past 20 years as a result of a better understanding of these rare tumors, by joining forces internationally. These frequent changes make it very difficult to exchange data or perform retrospective analyses. For optimal decision making, for a clear understanding and to allow reclassification according to the latest staging system, several items need to be described in the pathology report. This paper provides an overview of the essential items in reporting neuroendocrine neoplasms of the pancreaticobiliary and gastrointestinal tract.

The effect of long-acting somatostatin analogues on the uptake of [177Lu]Lu-HA-DOTATATE

PURPOSE

According to IAEA/EANM/SNMMI guidelines, long-acting somatostatin analogues (LA-SSAs) should be discontinued 4-6 weeks prior to peptide receptor radionuclide therapy (PRRT) to prevent somatostatin receptor saturation. The aim of this study was to determine the effect of continued use of long-acting SSAs during PRRT on the uptake of [177Lu]Lu-HA-DOTATATE on SPECT/CT.

METHODS

Consecutive patients with neuroendocrine tumours who were treated with PRRT receiving 7.4 GBq of [177Lu]Lu-HA-DOTATATE were included. Patients were divided into 3 groups: (1) control (LA-SSA stopped > 6 weeks prior to PRRT), or continued treatment with (2) long-acting octreotide < 6 weeks prior to PRRT, or (3) long-acting lanreotide < 6 weeks prior to PRRT. The uptake of [177Lu]Lu-HA-DOTATATE was quantified in healthy tissues (spleen, liver, kidneys, bone marrow) and tumour lesions on SPECT/CT performed 24 h after PRRT. A Mann-Whitney U test was used to determine differences in uptake between the long-acting octreotide and long-acting lanreotide groups compared to the control group.

RESULTS

Forty-two patients with 135 cycles of PRRT were included: 28 with lanreotide, 50 with octreotide, and 57 cycles without LA-SSAs. Uptake of [177Lu]Lu-HA-DOTATATE was significantly decreased in liver parenchyma in patients with lanreotide (p < 0.001) and in the spleen in patients with either octreotide or lanreotide (both p < 0.001). No differences were observed for uptake in kidneys, bone marrow, and blood pool. Uptake of [177Lu]Lu-HA-DOTATATE in tumours was the same in patients with lanreotide compared to the control (p = 0.862) and in patients with octreotide compared to the control (p = 0.201), independent of tumour location.

CONCLUSION

Long-acting octreotide and lanreotide do not interfere with the uptake of [177Lu]Lu-HA-DOTATATE in tumour lesions 24 h post-injection. Uptake in healthy liver parenchyma significantly decreases after lanreotide administration prior to PRRT, while uptake in healthy spleen tissue significantly decreases with both octreotide and lanreotide administration.

Neuroendocrine Tumor Diagnosis: PET/MR Imaging

Imaging plays a critical role in the diagnosis and management of neuroendocrine tumors (NETs). The initial workup of the primary tumor, including its characterization, local and distant staging, defines subsequent treatment decisions. Functional imaging using hybrid systems, such as PET combined with computed tomography, has become the gold standard. As NETs majorly arise from the gastrointestinal system and metastasize primarily to the liver, simultaneous PET and MR imaging with its high soft tissue contrast might be a valuable clinical one-stop-shop whole-body imaging tool. This review presents the current status and challenges of PET/MR imaging for diagnosis of NETs.

Interim Analysis of a Prospective Validation of 2 Blood-Based Genomic Assessments (PPQ and NETest) to Determine the Clinical Efficacy of 177Lu-DOTATATE in Neuroendocrine Tumors

Reliable biomarkers for neuroendocrine tumor (NET) management during peptide receptor radionuclide therapy (PRRT) are lacking. We validated the role of 2 circulating biomarkers: the PRRT prediction quotient (PPQ) as a predictive marker for response and the NETest as a monitoring biomarker. Furthermore, we evaluated whether tissue-based genetic alterations are effective in predicting progression-free survival (PFS). Methods: Data were prospectively collected on patients at the Memorial Sloan Kettering Cancer Center with 177Lu-DOTATATE-treated somatostatin receptor (SSTR)-positive gastroenteropancreatic and lung NETs (n = 67; median age, 66 y; 52% female; 42% pancreatic, 39% small-bowel; 78% grade 1 or 2). All cases were metastatic (89% liver) and had received 1-8 prior treatments (median, 3), including somatostatin analogs (91%), surgery (55%), or chemotherapy (49%). Treatment response included PFS. According to RECIST, version 1.1, responders had stable disease or a partial response (disease-control rate) and nonresponders had progression. Blood was collected before each cycle and at follow-up. Samples were deidentified and assayed and underwent masked analyses. The gene expression assays included RNA isolation, real-time quantitative polymerase chain reaction, and multialgorithm analyses. The PPQ (positive predicts a responder; negative predicts a nonresponder) at baseline was determined. The NETest (0-100 score) was performed. Statistics were analyzed using Mann-Whitney U testing (2-tailed) or Kaplan-Meier survival testing (PFS). In patients with archival tumor tissue, next-generation sequencing was performed through an institutional platform (Memorial Sloan Kettering-Integrated Mutation Profiling of Actionable Cancer Targets). Results: Forty-one patients (61%) were responders. PPQ accurately predicted 96% (64/67). The hazard ratio for prediction was 24.4 (95% CI, 8.2-72.5). Twelve-month disease control was 97% for PPQ-positive patients versus 26% for PPQ-negative patients (P < 0.0001). Median progression-free survival was not reached in those predicted to respond (PPQ-positive, n = 40) but was 8 mo in those predicted not to respond (PPQ-negative, n = 27). The NETest result in responders was 67 ± 25 at baseline and significantly (P < 0.05) decreased (-37 ± 44%) at follow-up. The NETest result in nonresponders was 44 ± 23 at baseline and significantly (P < 0.05) increased (+76% ± 56%) at progression. Overall, the NETest changes (increases or decreases) were 90% accurate. Thirty patients underwent next-generation sequencing. Tumors were microsatellite-stable, and the median mutational burden was 1.8. Alterations involved mainly the mTOR/PTEN/TSC pathway (30%). No relationship was associated with PRRT response. Conclusion: Our interim analysis confirmed that PPQ is an accurate predictor of 177Lu-DOTATATE responsiveness (radiosensitivity) and that NETest changes accurately correlated with treatment response. Tissue-based molecular genetic information had little value in PRRT prediction. Blood-based gene signatures may improve the management of patients undergoing 177Lu-DOTATATE by providing information on tumor radiosensitivity and disease course, thus allowing individualized strategies.

The Morphologic Spectrum of Gastric Type 1 Enterochromaffin-Like Cell Neuroendocrine Tumors

Although most well-differentiated gastric neuroendocrine tumors (gNETs) arise from enterochromaffin-like (ECL) cells in patients with autoimmune metaplastic atrophic gastritis (AMAG), the morphologic spectrum of these type 1 ECL-cell gNETs is not well defined. The extent of metaplastic progression in the background mucosa of AMAG patients with gNETs is likewise unclear. Here we report the histomorphology of 226 gNETs, including 214 type 1 gNETs (78 cases from 50 AMAG patients) pooled from a population with high AMAG prevalence. Most type 1 gNETs were ≤1.0 cm, of low grade, and multifocal, consistent with the results of previous reports. However, a high proportion (70/214, 33%) displayed unusual gNET morphologies not previously appreciated in AMAG patients. Unlike other type 1 gNETs with conventional neuroendocrine tumor morphologies, unconventional type 1 gNETs displayed cribriform networks of atrophic cells embedded within myxoid matrix (secretory-cribriform variant, 59%), sheets of deceptively bland discohesive cells resembling inflammatory infiltrates (lymphoplasmacytoid variant, 31%), or wreath-like arrangements of columnar cells wrapped around collagenous cores (pseudopapillary variant, 14%). Another unusual feature was that unconventional gNETs grew laterally within the mucosa (50/70, 71%) and were only rarely sampled from the submucosa (3/70, 4%). These features also differed from the conspicuous radial nodules (99/135, 73%) and frequent submucosal involvement (57/135, 42%) observed for conventional gNETs (P < .0001). Irrespective of morphology, type 1 gNETs were nearly always detected at first AMAG diagnosis (45/50, 90%) and tended to persist thereafter (34/43, 79%), despite similar clinical symptoms and laboratory values between AMAG patients with gNETs and those without. However, unlike AMAG patients without gNETs (n = 50), the background mucosa in patients with gNETs (n = 50) had already progressed to the morphologic equivalent of end-stage metaplasia (P < .0001). This included diffuse loss of parietal cells (92% vs 52%), complete intestinal metaplasia (82% vs 40%), and pancreatic metaplasia (56% vs 6%). Thus, type 1 ECL-cell gNETs are morphologically heterogeneous with a high prevalence of unconventional gNET morphologies. They tend to present silently at first AMAG diagnosis as multifocal lesions that persist within fields of mature metaplasia.

Pancreatic imaging in MEN1-Comparison of conventional and SSTR PET/CT imaging in real-life setting

OBJECTIVE

Pancreatic neuroendocrine tumors (panNETs) are the leading cause of death in patients with multiple endocrine neoplasia type 1 (MEN1). The role of somatostatin receptor positron emission tomography (SSTR PET/CT) in MEN1 has not been established. The aim was to assess pancreatic imaging in MEN1 in a real-life setting.

DESIGN AND METHODS

Fifty-eight patients with MEN1 (median age 40 (range 16-72) years) underwent SSTR PET/CT imaging; either as a screening tool regardless of disease stage (n = 47) or to further characterize known panNETs (n = 11). SSTR PET/CT and matched conventional imaging were blindly analyzed. We assessed the findings and the impact of SSTR PET/CT during a median follow-up of 47 months.

RESULTS

SSTR PET/CT detected three times as many panNETs as conventional imaging (p < 0.001). SSTR PET/CT altered the management of 27 patients (47%). Seven patients (12%) were referred for surgery, and five (9%) received systemic treatment. In 15/25 (60%) patients with no previous panNET (n = 22) or in remission after surgery (n = 3), SSTR PET/CT identified a panNET (n = 14) or recurrence (n = 1). In eight patients, SSTR PET/CT revealed a panNET not immediately visible on conventional imaging. During a median follow-up of 47 months, three became visible on conventional imaging, but none required intervention. When SSTR PET/CT was negative, no panNETs were identified on conventional imaging during 38 months of follow-up.

CONCLUSIONS

SSTR PET/CT demonstrates high accuracy in the detection of panNETs and alters the clinical management in nearly half of the MEN1-patients. SSTR PET/CT enables timely diagnosis and staging of MEN1-related panNETs.

CT-based radiomics to distinguish progressive from stable neuroendocrine liver metastases treated with somatostatin analogues: an explorative study

BACKGROUND

Accurate response evaluation in patients with neuroendocrine liver metastases (NELM) remains a challenge. Radiomics has shown promising results regarding response assessment.

PURPOSE

To differentiate progressive (PD) from stable disease (SD) with radiomics in patients with NELM undergoing somatostatin analogue (SSA) treatment.

MATERIAL AND METHODS

A total of 46 patients with histologically confirmed gastroenteropancreatic neuroendocrine tumors (GEP-NET) with ≥1 NELM and ≥2 computed tomography (CT) scans were included. Response was assessed with Response Evaluation Criteria in Solid Tumors (RECIST1.1). Hepatic target lesions were manually delineated and analyzed with radiomics. Radiomics features were extracted from each NELM on both arterial-phase (AP) and portal-venous-phase (PVP) CT. Multiple instance learning with regularized logistic regression via LASSO penalization (with threefold cross-validation) was used to classify response. Three models were computed: (i) AP model; (ii) PVP model; and (iii) AP + PVP model for a lesion-based and patient-based outcome. Next, clinical features were added to each model.

RESULTS

In total, 19 (40%) patients had PD. Median follow-up was 13 months (range 1-50 months). Radiomics models could not accurately classify response (area under the curve 0.44-0.60). Adding clinical variables to the radiomics models did not significantly improve the performance of any model.

CONCLUSION

Radiomics features were not able to accurately classify response of NELM on surveillance CT scans during SSA treatment.

Staphylococcus aureus extracellular adherence protein (Eap) reduces immune cell phenotype in developing but not in established atherosclerotic lesions

Atherosclerosis is a chronic, inflammatory disease of the vessel wall where triggered immune cells bind to inflamed endothelium, extravasate and sustain local inflammation. Leukocyte adhesion and extravasation are mediated by adhesion molecules expressed by activated endothelial cells, like intercellular adhesion molecule 1 (ICAM-1). Extracellular adherence protein (Eap) from Staphylococcus aureus binds to a plethora of extracellular matrix proteins, including ICAM-1 and its ligands macrophage-1 antigen (Mac-1, αMβ2) and lymphocyte function-associated antigen 1 (LFA-1, αLβ2), thereby disrupting the interaction between leukocytes and endothelial cells. We aimed to use Eap to inhibit the interaction of leukocytes with activated endothelial cells in settings of developing and established atherosclerosis in apolipoprotein E (ApoE) deficient mice on high-fat diet. In developing atherosclerosis, Eap treatment reduced circulating platelet-neutrophil aggregates as well as infiltration of T cells and neutrophils into the growing plaque, accompanied by reduced formation of neutrophil extracellular traps (NETs). However, plaque size did not change. Intervention treatment with Eap of already established plaques did not result in cellular or morphological plaque changes, whereas T cell infiltration was increased and thereby again modulated by Eap. We conclude that although Eap leads to cellular changes in developing plaques, clinical implications might be limited as patients are usually treated at a more advanced stage of disease progression. Hence, usage of Eap might be an interesting mechanistic tool for cellular infiltration during plaque development in basic research but not a clinical target.

Management of rectal neuroendocrine tumours by transanal endoscopic microsurgery

AIM

The objective of this study was to evaluate the safety and effectiveness of transanal endoscopic microsurgery for rectal neuroendocrine tumours.

METHOD

A retrospective cohort study of all pathology-confirmed rectal neuroendocrine tumours treated by transanal endoscopic microsurgery from April 2007 to December 2020 at a tertiary care centre was performed. Demographic, clinical, radiographic and pathological data were collected. Characteristics of patients with recurrence were examined. Descriptive statistics were performed.

RESULTS

There were 58 patients treated by transanal endoscopic microsurgery excision. Referrals were for primary excision (15, 25.9%), completion re-excision after incomplete endoscopic removal (38, 65.5%) or locally recurrent rectal neuroendocrine tumours (5, 8.6%). The mean age of patients was 56.4 ± 11.9 years and 26 patients were women (44.8%). Mean tumour size was 7.4 ± 3.8 mm (range 1.0-15.0 mm). Most (86.4%) were Grade 1 tumours. Mean operative time was 37.2 ± 17.2 min and 56 patients (96.6%) were discharged on the same day. All patients had negative margins on final pathology. Of the 38 patients who were referred for completion re-excision after incomplete endoscopic removal, eight (21.1%) had residual tumour on final pathology. Three recurrences were diagnosed at 2.1, 4.5 and 12.5 years after excision. All recurrences were from Grade 1 or 2 primary tumours, less than 2 cm, and diagnosed radiographically.

CONCLUSION

To date, this is the largest North American study looking at transanal endoscopic microsurgery for rectal neuroendocrine tumours. This technique is effective in managing primary, incompletely excised and recurrent tumours with good clinical and oncological outcomes.

Comparison of somatostatin receptor expression in patients with neuroendocrine tumours with and without somatostatin analogue treatment imaged with [18F]SiTATE

Purpose

Somatostatin analogues (SSA) are frequently used in the treatment of neuroendocrine tumours. Recently, [18F]SiTATE entered the field of somatostatin receptor (SSR) positron emission tomography (PET)/computed tomography (CT) imaging. The purpose of this study was to compare the SSR-expression of differentiated gastroentero-pancreatic neuroendocrine tumours (GEP-NET) measured by [18F]SiTATE-PET/CT in patients with and without previous treatment with long-acting SSAs to evaluate if SSA treatment needs to be paused prior to [18F]SiTATE-PET/CT.

Methods

77 patients were examined with standardised [18F]SiTATE-PET/CT within clinical routine: 40 patients with long-acting SSAs up to 28 days prior to PET/CT examination and 37 patients without pre-treatment with SSAs. Maximum and mean standardized uptake values (SUVmax and SUVmean) of tumours and metastases (liver, lymphnode, mesenteric/peritoneal and bones) as well as representative background tissues (liver, spleen, adrenal gland, blood pool, small intestine, lung, bone) were measured, SUV ratios (SUVR) were calculated between tumours/metastases and liver, likewise between tumours/metastases and corresponding specific background, and compared between the two groups.

Results

SUVmean of liver (5.4 ± 1.5 vs. 6.8 ± 1.8) and spleen (17.5 ± 6.8 vs. 36.7 ± 10.3) were significantly lower (p < 0.001) and SUVmean of blood pool (1.7 ± 0.6 vs. 1.3 ± 0.3) was significantly higher (p < 0.001) in patients with SSA pre-treatment compared to patients without. No significant differences between tumour-to-liver and specific tumour-to-background SUVRs were observed between both groups (all p > 0.05).

Conclusion

In patients previously treated with SSAs, a significantly lower SSR expression ([18F]SiTATE uptake) in normal liver and spleen tissue was observed, as previously reported for 68Ga-labelled SSAs, without significant reduction of tumour-to-background contrast. Therefore, there is no evidence that SSA treatment needs to be paused prior to [18F]SiTATE-PET/CT.

Spectral Computed Tomography-Derived Iodine Content and Tumor Response in the Follow-Up of Neuroendocrine Tumors-A Single-Center Experience

Spectral computed tomography (SCT) allows iodine content (IC) calculation for characterization of hypervascularized neoplasms and thus might help in the staging of neuroendocrine tumors (NETs). This single-center prospective study analyzed the association between SCT-derived IC and tumor response in the follow-up of metastasized NETs. Twenty-six patients with a median age of 70 years (range 51-85) with histologically proven NETs and a total of 78 lesions underwent SCT for staging. Because NETS are rare, no primary NET types were excluded. Lesions and intralesional hotspots were measured in virtual images and iodine maps. Tumor response was classified as progressive or nonprogressive at study endpoint. Generalized estimating equations served to estimate associations between IC and tumor response, additionally stratified by lesion location. Most commonly affected sites were the lymph nodes, liver, pancreas, and bones. Median time between SCT and endpoint was 64 weeks (range 5-260). Despite statistical imprecision in the estimate, patients with higher IC in lymphonodular metastases had lower odds for disease progression (adjusted OR = 0.21, 95% CI: 0.02-2.02). Opposite tendencies were observed in hepatic and pancreatic metastases in unadjusted analyses, which vanished after adjusting for therapy and primary tumor grade.

Contrast Enhanced EUS for Predicting Solid Pancreatic Neuroendocrine Tumor Grade and Aggressiveness

Pancreatic neuroendocrine tumor (PNET) behavior assessment is a daily challenge for physicians. Modern PNET management varies from a watch-and-wait strategy to surgery depending on tumor aggressiveness. Therefore, the aggressiveness definition plays a pivotal role in the PNET work-up. The aggressiveness of PNETs is mainly based on the dimensions and histological grading, with sometimes a lack of specificity and sensibility. In the last twenty years, EUS has become a cornerstone in the diagnostic phase of PNET management for its high diagnostic yield and the possibility of obtaining a histological specimen. The number of EUS applications in the PNET work-up has been rapidly increasing with new and powerful possibilities. The application of contrast has led to an important step in PNET detection; in recent years, it has been gaining interesting applications in aggressiveness assessment. In this review, we underline the latest experiences and opportunities in the behavior assessment of PNETs using contact-enhanced EUS and contested enhanced harmonic EUS with a particular focus on the future application and possibility that these techniques could provide.

In silico study on the binding interactions of SSTA and 18F-SSTA towards somatostatin receptor subtype 2

BACKGROUND

Somatostatin analogs (SSTAs) are versatile drugs that target a group of proteins known as somatostatin receptors. SSTAs are used for the treatment and PET-molecular imaging of Neuro Endocrine Tumors (NET), for which they are labeled with the radionuclide 18F, a positron emitter radionuclide.

OBJECTIVE

The aim of this work was to theoretically study the binding interactions of SSTA labeled with 18F (half-life of 109.7 min) and somatostatin receptor subtype 2. As the labeling of SSTA with 18F required the use of a prosthetic group, a hydrophilicity enhancer, and a linker, the influence of these traits on the interactions of 18F-SSTA with the SSTR-2 binding site was studied.

METHODS

The binding modes of 18F-labeled analogues with SSTR-2 were studied by using protein homology modelling, non-equilibrium molecular dynamics, and molecular docking calculations, by means of three docking software: MVD, MOE, and VINA.

RESULTS

The results showed the main role of Asp122, Asn276, and Phe272, Phe294 from the SSTR-2 binding site, which form interactions with residues Lys, Trp, Tyr, and Thr from 18F-labeled somatostatin analogues.

CONCLUSION

The interaction between Lys (from 18F-SSTA) and Asp122 (from SSTR-2) was identified as the most energetic and considered the one that drives the binding between 18F-SSTA and SSTR-2 (the anchor interaction). Despite the presence of prosthetic groups, linkers, and hydrophilicity enhancers, all the studied 18F-SSTA formed the anchor interaction. The trend in the results agreed with the experimental reports, identifying the main role of Asp122 in the binding of somatostatin-14 to SSTR-2.

Neutrophils in Dendritic Cell-Based Cancer Vaccination: The Potential Roles of Neutrophil Extracellular Trap Formation

Neutrophils have conflicting roles in the context of cancers, where they have been associated with contributing to both anti-tumor and pro-tumor responses. Their functional heterogenicity is plastic and can be manipulated by environmental stimuli, which has fueled an area of research investigating therapeutic strategies targeting neutrophils. Dendritic cell (DC)-based cancer vaccination is an immunotherapy that has exhibited clinical promise but has shown limited clinical efficacy. Enhancing our understanding of the communications occurring during DC cancer vaccination can uncover opportunities for enhancing the DC vaccine platform. There have been observed communications between neutrophils and DCs during natural immune responses. However, their crosstalk has been poorly studied in the context of DC vaccination. Here, we review the dual functionality of neutrophils in the context of cancers, describe the crosstalk between neutrophils and DCs during immune responses, and discuss their implications in DC cancer vaccination. This discussion will focus on how neutrophil extracellular traps can influence immune responses in the tumor microenvironment and what roles they may play in promoting or hindering DC vaccine-induced anti-tumor efficacy.

Small-Cell Carcinoma of Nasopharynx: A Case Report of Unusual Localization

Neuroendocrine tumors are a spectrum of rare and highly heterogeneous neoplasms with distinct functional and biological behavior in relation to location, tumor size, and histological differentiation. Neuroendocrine tumors arise from the neuroendocrine cells of the diffuse neuroendocrine system located in almost every organ. Neuroendocrine tumors in the head and neck district are usually reported in sinonasal cavities and larynx. We present the case of a nasopharyngeal small-cell neuroendocrine carcinoma, which, as far as we know, is the 16th case reported in literature.

The role of selenoproteins in neutrophils during inflammation

Polymorphonuclear neutrophils (PMNs)-derived ROS are involved in the regulation of multiple functions of PMNs critical in both inflammation and its timely resolution. Selenium is an essential trace element that functions as a gatekeeper of cellular redox homeostasis in the form of selenoproteins. Despite their well-studied involvement in regulating functions of various immune cells, limited studies have focused on the regulation of selenoproteins in PMN and their associated functions. Ex-vivo treatment of murine primary bone marrow derived PMNs with bacterial endotoxin lipopolysaccharide (LPS) indicated temporal regulation of several selenoprotein genes at the mRNA level. However, only glutathione peroxidase 4 (Gpx4) was significantly upregulated, while Selenof, Selenow, and Gpx1 were significantly downregulated in a temporal manner at the protein level. Exposure of PMNs isolated from tRNASec (Trsp)fl/fl S100A8Cre (TrspN) PMN-specific selenoprotein knockout mice, to the Gram-negative bacterium, Citrobacter rodentium, showed decreased bacterial growth, reduced phagocytosis, as well as impaired neutrophil extracellular trap (NET) formation ability, when compared to the wild-type PMNs. Increased extracellular ROS production upon LPS stimulation was also observed in TrspN PMNs that was associated with upregulation of Alox12, Cox2, and iNOS, as well as proinflammatory cytokines such as TNFα and IL-1β. Our data indicate that the inhibition of selenoproteome expression results in alteration of PMN proinflammatory functions, suggesting a potential role of selenoproteins in the continuum of inflammation and resolution.

Neutrophil extracellular traps have auto-catabolic activity and produce mononucleosome-associated circulating DNA

BACKGROUND

As circulating DNA (cirDNA) is mainly detected as mononucleosome-associated circulating DNA (mono-N cirDNA) in blood, apoptosis has until now been considered as the main source of cirDNA. The mechanism of cirDNA release into the circulation, however, is still not fully understood. This work addresses that knowledge gap, working from the postulate that neutrophil extracellular traps (NET) may be a source of cirDNA, and by investigating whether NET may directly produce mono-N cirDNA.

METHODS

We studied (1) the in vitro kinetics of cell derived genomic high molecular weight (gHMW) DNA degradation in serum; (2) the production of extracellular DNA and NET markers such as neutrophil elastase (NE) and myeloperoxidase (MPO) by ex vivo activated neutrophils; and (3) the in vitro NET degradation in serum; for this, we exploited the synergistic analytical information provided by specifically quantifying DNA by qPCR, and used shallow WGS and capillary electrophoresis to perform fragment size analysis. We also performed an in vivo study in knockout mice, and an in vitro study of gHMW DNA degradation, to elucidate the role of NE and MPO in effecting DNA degradation and fragmentation. We then compared the NET-associated markers and fragmentation size profiles of cirDNA in plasma obtained from patients with inflammatory diseases found to be associated with NET formation and high levels of cirDNA (COVID-19, N = 28; systemic lupus erythematosus, N = 10; metastatic colorectal cancer, N = 10; and from healthy individuals, N = 114).

RESULTS

Our studies reveal that gHMW DNA degradation in serum results in the accumulation of mono-N DNA (81.3% of the remaining DNA following 24 h incubation in serum corresponded to mono-N DNA); "ex vivo" NET formation, as demonstrated by a concurrent 5-, 5-, and 35-fold increase of NE, MPO, and cell-free DNA (cfDNA) concentration in PMA-activated neutrophil culture supernatant, leads to the release of high molecular weight DNA that degrades down to mono-N in serum; NET mainly in the form of gHMW DNA generate mono-N cirDNA (2 and 41% of the remaining DNA after 2 h in serum corresponded to 1-10 kbp fragments and mono-N, respectively) independent of any cellular process when degraded in serum; NE and MPO may contribute synergistically to NET autocatabolism, resulting in a 25-fold decrease in total DNA concentration and a DNA fragment size profile similar to that observed from cirDNA following 8 h incubation with both NE and MPO; the cirDNA size profile of NE KO mice significantly differed from that of the WT, suggesting NE involvement in DNA degradation; and a significant increase in the levels of NE, MPO, and cirDNA was detected in plasma samples from lupus, COVID-19, and mCRC, showing a high correlation with these inflammatory diseases, while no correlation of NE and MPO with cirDNA was found in HI.

CONCLUSIONS

Our work describes the mechanisms by which NET and cirDNA are linked. In doing so, we demonstrate that NET are a major source of mono-N cirDNA independent of apoptosis and establish a new paradigm of the mechanisms of cirDNA release in normal and pathological conditions. We also demonstrate a link between immune response and cirDNA.

The expanding family of neutrophil-derived extracellular vesicles

Neutrophils are immune cells involved in several inflammatory and homeostatic processes. Their capacity to release cargo can be classified based on whether the cargo is released on its own, or in conjunction with plasma membrane structures. Examples of plasma membrane-free secretion modes are degranulation, neutrophil extracellular trap (NET) release, and cytokine release through inflammasome formation. The most studied membrane-covered neutrophil-derived structures are exosomes and ectosomes that are collectively called extracellular vesicles (EV). Apoptotic vesicles are another recognized EV subtype. Over the last decade, additional membrane-covered neutrophil-derived structures were characterized: migratory cytoplasts, migrasomes, and elongated neutrophil-derived structures (ENDS). All these structures are smaller than the neutrophils, cannot reproduce themselves, and thus meet the latest consensus definition of EVs. In this review, we focus on the less well-studied neutrophil EVs: apoptotic vesicles, cytoplasts, migrasomes, and ENDS.

Single centre retrospective review of outcome of 177 Lu-DOTATATE peptide receptor radionuclide therapy in the treatment of progressive metastatic neuroendocrine tumours: Survival, toxicity, and prognostic factors

The aim of this study was to evaluate the efficacy and safety of ¹⁷⁷ Lu-DOTATATE therapy in advanced metastatic disease. A retrospective analysis of 395 patients (180 female, 215 males, mean age 62) with progressive metastatic neuroendocrine tumours (NETs) who were treated with ¹⁷⁷ Lu-DOTATATE was performed. Overall, 115 patients had less than four cycles and 280 completed four cycles of treatment. Progression-free survival (PFS) and overall survival (OS) was performed using Kaplan-Meier analysis. Analysis of survival predictors was performed using Cox regression model. Toxicity was defined using the Common Terminology Criteria for Adverse Events version 5 (CTCAE 5.0). The percentage of patients with liver and skeletal metastases were 91 and 57%, respectively. Median PFS and OS were calculated at 33 months (95% CI: 29-37 months) and 46 months (95% CI: 48-56 months), respectively. End of treatment response assessment was performed using cross sectional imaging demonstrated partial response in 22%, stable disease in 64% and progressive disease in 14% of patients. Overall, grade 3 and 4 bone marrow toxicity was seen in 8%. One patient (0.3%) developed irreversible grade 4 nephrotoxicity. Myelodysplastic disease was recorded in one patient (0.3%). Univariate analysis of PFS predictors showed that body mass index (BMI), baseline chromogranin A (CgA) >400 ng/l, baseline alkaline phosphatase (ALP) >130 mg/dl, liver tumour volume and overall tumour burden were significant. On multivariate analysis only Ki67, high CgA and low BMI retained significance. ¹⁷⁷ Lu-DOTATATE is an effective treatment in advanced NETs with generally high-volume metastases. It is well-tolerated. Ki-67, CgA and BMI appear to be predictors for PFS.