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Background: Metastatic neuroendocrine carcinoma (NEC) is associated with short survival. Other than platinum-based chemotherapy, there is no clear standard regimen. Current guidelines suggest that combination treatment with BRAF-inhibitors should be considered for patients with BRAF V600E-mutated NEC. However, since only eight such patients have been reported in the literature, our object was to confirm the validity of this recommendation.

Methods: This was a single-center retrospective cohort study conducted at Uppsala University Hospital. The included patients 1) had a histopathologically confirmed diagnosis of NEC, 2) were diagnosed between January 1^st, 2018 and December 31^st, 2023, 3) had tumor tissue genetically screened by a broad next-generation sequencing (NGS) panel, and 4) showed a tumor mutation for which there is a currently available targeted therapy.

Results: We screened 48 patients diagnosed with NEC between January 1^st, 2018 and December 31^st, 2023. Twelve had been analyzed with a broad NGS-panel, and two had a targetable mutation. Both these patients harbored a BRAF V600E-mutated colon-NEC and were treated with BRAF- and MEK-inhibitors dabrafenib and trametinib in second-line. At first radiological evaluation (RECIST 1.1), both patients had a reduction of tumor size, which decreased by 31 and 40%. Both had short response periods, and their overall survival was 12 and 9 months.

Conclusions: BRAF-mutated NEC is sensitive to treatment with BRAF- and MEK-inhibitor combination. These results further support that DNA sequencing should be considered as standard of care in NECs to screen for potential treatment targets.

Tumour evolution with acquisition of more aggressive disease characteristics is a hallmark of disseminated cancer. Metastatic pancreatic neuroendocrine tumours (PanNETs) in particular may progress from a low/intermediate to a high-grade disease. The aim of this work was to understand the molecular mechanisms underlying metastatic progression as well as PanNET transformation from a low/intermediate to a high-grade disease. We performed multi-omics analysis (genome/exome sequencing, total RNA-sequencing and methylation array) of 32 longitudinal samples from six patients with metastatic low/intermediate grade PanNET. The clonal composition of tumour lesions and underlying phylogeny of each patient were determined with bioinformatics analyses. Findings were validated in post-alkylating chemotherapy samples from 24 patients with PanNET using targeted next generation sequencing. We validate the current PanNET evolutionary model with MEN1 inactivation that occurs very early in tumourigenesis. This was followed by pronounced genetic diversity on both spatial and temporal levels, with parallel and convergent tumour evolution involving the ATRX/DAXX and mechanistic target of the rapamycin (mTOR) pathways. Following alkylating chemotherapy treatment, some PanNETs developed mismatch repair deficiency and acquired a hypermutational phenotype. This was validated among 16 patients with PanNET who had high-grade progression after alkylating chemotherapy, of whom eight had a tumour mutational burden >50 (50%). In comparison, among the eight patients who did not show high-grade progression, 0 had a tumour mutational burden >50 (0%; odds ratio ‘infinite’, 95% confidence interval 1.8 to ‘infinite’, p = 0.02). Our findings contribute to broaden the understanding of metastatic/high-grade PanNETs and suggests that therapy driven disease evolution is an important hallmark of this disease.

Core needle biopsy (CNB) has been used with caution in pheochromocytoma and paraganglioma (PPGL) due to concerns about catecholamine-related complications. While it is unclear what scientific evidence supports this claim, it has limited the acquisition of biological samples for diagnostic purposes and research, especially in metastatic PPGL. We performed a systematic review and individual patient meta-analysis to evaluate the risk of complications after CNB in PPGL patients. The primary and secondary objectives were to investigate the risk of death and the occurrence of complications requiring intervention or hospitalization, respectively. Fifty-six articles describing 86 PPGL patients undergoing CNB were included. Of the patients (24/71), 34% had metastases and 53.4% (31/58) had catecholamine-related symptoms before CNB. Of the patients (14/41), 34.1% had catecholamine excess testing prior to the biopsy. No CNB-related deaths were reported. Four patients (14.8%, 4/27) experienced CNB-related complications requiring hospitalization or intervention. One case had a temporary duodenal obstruction caused by hematoma, two cases had myocardial infarction, and one case had Takotsubo cardiomyopathy. Eight patients (32%, 8/25) had CNB-related catecholamine symptoms, mainly transient hypertension, excessive diaphoresis, tachycardia, or hypertensive crisis. The scientific literature does not allow us to make any firm conclusion on the safety of CNB in PPGL. However, it is reasonable to argue that CNB could be conducted after thorough consideration, preparation, and with close follow-up for PPGL patients with a strong clinical indication for such investigation.

Longitudinal changes in pancreatic neuroendocrine tumor (panNET) cell proliferation correlate with fast disease progression and poor prognosis. The optimal treatment strategy for secondary panNET grade (G)3 that has progressed from a previous low- or intermediate-grade to high-grade panNET G3 is currently unknown. This was a single-center retrospective cohort study aimed to characterize treatment patterns and outcomes among patients with secondary panNET-G3. Radiological responses were assessed using the Response Evaluation Criteria in Solid Tumors version 1.1. A total of 22 patients were included and received a median of 2 (range, 1–4) treatment lines in 14 different combinations. Median overall survival (OS) was 9 months (interquartile range (IQR): 4.25–17.5). For the 15 patients who received platinum–etoposide chemotherapy, median OS was 7.5 months (IQR: 3.75–10) and median progression-free survival (PFS) was 4 months (IQR: 2.5–5.5). The 15 patients who received conventional panNET therapies achieved a median OS of 8 months (IQR: 5–16.75) and median PFS was 5.5 months (IQR: 2.75–8.25). We observed one partial response on ¹⁷⁷Lu DOTA-TATE therapy. In conclusion, this hypothesis-generating study failed to identify any promising treatment alternatives for patients with secondary panNET-G3. This demonstrates the need for both improved biological understanding of this particular NET entity and for designing prospective studies to further assess its treatment in larger patient cohorts.

PURPOSE: With the ambition of improving the management of pancreatic neuroendocrine tumors (P-NETs), we developed and preliminary validated a novel fluorine-18 labelled HSP₉₀ ligand.

METHODS: A precursor containing methoxymethyl ethers protecting groups and a tosyl as leaving group was synthesized. The target compound was labeled with nucleophilic ¹⁸F-fluoride and the protecting groups was subsequently removed with hydrochloric acid before purification. In vitro cell- and frozen section autoradiography and in vivo animal studies were performed.

RESULTS: The precursor was successfully synthesized and utilized in the ¹⁸F-radiolabeling giving 0.5-1.0 GBq of pure product with a synthesis time of 70 min. In vitro experiments indicated a high specific binding, but in vivo studies showed no tumor uptake due to fast hepatobiliary metabolism and excretion.

CONCLUSIONS: Despite the unfavorable in vivo properties of the tracer, the promising results from in vitro autoradiography experiments in frozen sections of P-NETs from surgical resection encourage us to continue the project aiming the improvement of in vivo properties of the tracer.

Adrenocortical carcinoma is a rare aggressive disease commonly recurring regardless of radical surgery. Although data on genomic alterations in malignant tumors are accumulating, knowledge of molecular events of importance for initiation of adrenocortical transformation is scarce. In an attempt to recognize early molecular alterations, we used adrenals from young multiple endocrine neoplasia type 1 conventional knock-out mice (Men1(+/-)) closely mimicking the human MEN1 trait (i.e. transformation of pituitary, parathyroid, endocrine pancreatic, and adrenocortical cells). MicroRNA array and hierarchical clustering showed a distinct pattern. Twenty miRNAs were significantly upregulated and eleven were downregulated in Men1(+/-) compared to wild type littermates. The latter included the known suppressor miRNA miR-486-3p, which was chosen for transfection in human adrenocortical carcinoma cell lines H295R and SW13. Cell growth decreased in miR-486-3p overexpressing clones and levels of the predicted target gene fatty acid synthase (FASN) and its downstream product, palmitic acid, were lowered. In conclusion, heterozygous inactivation of Men1 in adrenals results in distinct miRNA profile regulating expression of genes with impact on tumorigenesis, e.g. transcription, nucleic acid and lipid metabolism. Low levels of miR-486-3p in the early stages of transformation may contribute to proliferation by increasing FASN and thus fatty acid production. FASN as a potentially druggable target for treatment of the devastating disease adrenocortical carcinoma warrants further studies.

Among patients with the rare diagnosis of pancreatic neuroendocrine tumor (P-NET), a substantial proportion suffer from the inherited cancer syndrome multiple endocrine neoplasia type 1 (MEN1), which is caused by germline mutations of the MEN1 suppressor gene. Somatic mutations and loss of the MEN1 protein (menin) are frequently also found in sporadic P-NETs. Thus, a human neuroendocrine pancreatic cell line with biallelic inactivation of MEN1 might be of value for studying tumorigenesis. We used the polyclonal human P-NET cell line BON1, which expresses menin, serotonin, chromogranin A and neurotensin, to generate a monoclonal stable MEN1 knockout BON1 cell line (MEN1-KO-BON1) by CRISPR/Cas9 editing. Changes in morphology, hormone secretion, and proliferation were analyzed, and proteomics were assessed using nanoLC-MS/MS and Ingenuity Pathway Analysis (IPA). The menin-lacking MEN1-KO-BON1 cells had increased chromogranin A production and were smaller, more homogenous, rounder and grew faster than their control counterparts. Proteomic analysis revealed 457 significantly altered proteins, and IPA identified biological functions related to cancer, e.g., posttranslational modification and cell death/survival. Among 39 proteins with at least a two-fold difference in expression, twelve are relevant in glucose homeostasis and insulin resistance. The stable monoclonal MEN1-KO-BON1 cell line was found to have preserved neuroendocrine differentiation, increased proliferation, and an altered protein profile.

INTRODUCTION: Little is known about how Pancreatic Neuroendocrine Tumors (PanNETs) evolve over time and if changes towards a more aggressive biology correlates with prognosis. The purpose of this study was to characterize changes PanNET differentiation and proliferation over time, and to correlate findings to overall survival (OS).

PATIENTS AND METHODS: In this retrospective cohort study we screened 475 PanNET patients treated at Uppsala University Hospital, Sweden. Sporadic patients with baseline and follow-up tumor samples were included. Pathology reports and available tissue sections were re-evaluated with regard to tumor histopathology and Ki-67 index.

RESULTS: Forty-six patients with 106 tumor samples (56 available for pathology re-evaluation) were included. Median Ki-67 index at diagnosis was 7% (range 1-38%), grade 1 n=8, grade 2 n=36, and grade 3 n=2. The median change in Ki-67 index (absolute value; follow-up - baseline) was +14% (range -11 to +80%). Increase in tumor grade occurred in 28 patients (63.6%), the majority from grade 1/2 to grade 3 (n=24, 54.5%). The patients with a high-grade progression had a median OS of 50.2 months compared to 115.1 months in patients without such progression (HR 3.89, 95% CI 1.91-7.94, P<0.001).

CONCLUSIONS: A longitudinal increase in Ki-67 index and increase in tumor grade were observed in a majority of PanNETs included in this study. We propose that increase in Ki-67 index and high-grade progression should be investigated further as important biomarkers in PanNET.

OBJECTIVE:Multiple Endocrine Neoplasia type 1 (MEN1) is an autosomal dominant syndrome usually caused by loss-of-function mutations in the MEN1-gene. However, a minority of patients who fulfill the criteria for MEN1 are not found to harbor MEN1-mutations. Besides, some of these individuals, present with a subtly different phenotype suggestive of sporadic disease. The aim of the present study was to investigate the genetic architecture of mutation-negative MEN1. DESIGN:Fourteen patients with a clinical diagnosis (n=13) or suspicion (n=1) of MEN1 who had negative genetic screening of the MEN1 gene were included. METHODS:Constitutional DNA from the included patients, as well as tumor DNA from six of the patients, was subjected to whole genome sequencing. Constitutional variants were filtered against population databases and somatic variants were studied under a tumor-suppressor model. RESULTS:Three patients carried pathogenic variants (two splice-site variants, one missense variant) in MEN1 that had not been detected during routine clinical sequencing, one patient carried a pathogenic variant in CASR and one patient carried a gross deletion on chromosome 1q which included the CDC73 gene. Analysis of matched tumor DNA from six patients without mutations did not detect any recurrent genes fulfilling Knudson's two-hit model. CONCLUSION:These results highlight the possibility of germline mutations being missed in routine screening, the importance of considering phenocopies in atypical or mutation-negative cases. The absence of apparent disease-causing mutations suggests that a fraction of MEN1 mutation negative MEN1 cases may be due to the chance occurrence of several endocrine tumors in one patient.