Neuroendocrine liver metastases treated using transarterial radioembolization: Identification of prognostic parameters at 68Ga-DOTATATE PET/CT.

PURPOSE: To identify prognostic clinical and imaging parameters for patients with neuroendocrine liver metastases (NELMs) undergoing transarterial radioembolization (TARE). MATERIALS AND METHODS: Forty-seven patients (27 men; mean age, 64 years) with NELMs who received TARE, along with pre-procedure liver MRI and 68Ga-DOTATATE positron emission tomography/computed tomography were included. Apparent diffusion coefficient and standardized uptake value (SUV) of three liver metastases, normal spleen and liver were measured. SUVmax or SUVmean were used for the calculation of tumor-to-organ ratios (tumor-to-spleen and tumor-to-liver ratios) using all possible combinations (including SUVmax/SUVmax, SUVmax/SUVmean, and SUVmean/SUVmean). Clinical parameters (hepatic tumor-burden, presence of extra-hepatic metastases, chromograninA, Ki-67 and bilirubin levels) were assessed. Overall survival, progression-free survival (PFS) and hepatic progression-free survival (HPFS) were calculated using Kaplan-Meier curves. RESULTS: Median overall survival, PFS and HPFS were 49.6, 13.1 and 28.3 months, respectively. In multivariable Cox regression analysis, low Ki-67 (≤ 5%), low hepatic tumor-burden (< 10%), absence of extrahepatic metastases, and increased Tmean/Lmax ratio were significant prognostic factors of longer overall survival and HPFS. High baseline chromograninA (> 1330 ng/mL) was associated with shorter HPFS. Tmean/Lmax > 1.9 yielded a median overall survival of 69 vs. 33 months (P < 0.04), and a median HPFS of 30 vs. 19 months (P = 0.09). For PFS, high baseline SUVmax of NELMs was the single significant parameter in the multivariable model. SUVmax > 28 resulted in a median PFS of 16.9 vs. 6.5 months, respectively (P = 0.001). CONCLUSION: High preinterventional Tmean/Lmax ratios, and high SUVmax on 68Ga-DOTATATE positron emission tomography/computed tomography seem to have prognostic value in patients with NELMs undergoing TARE, potentially aiding patient selection and management alongside conventional variables.

Impact of tumor size and location on endoscopic ultrasound-guided sampling of pancreatic neuroendocrine tumors: A recursive partitioning analysis.

BACKGROUND: Current guidelines provide weak recommendations to treat small (<2 cm) non-functional pancreatic neuroendocrine tumors with low Ki-67 proliferation index either by resection or clinical follow-up. However, there is a lack of consensus regarding the minimal size of pNET, which allows EUS-guided biopsy with high enough diagnostic accuracy for stratification. METHODS: We conducted a retrospective, bicentric analysis of patients who had undergone EUS-guided pNET sampling in two tertiary care Endoscopy Units in Germany and Poland. Using a recursive partitioning of the tree-aided model, we aimed to stratify the probability of successful EUS-guided biopsy of pNET lesions according to their size and location. RESULTS: In our pNET cohort, successful histological confirmation of a pNET diagnosis was achieved in 59/69 (85.5%) cases at the initial EUS-guided biopsy. In 41 patients with a pNET size less than 18.5 mm, the EUS-guided first biopsy was successful in 90.2%. In 16 of these patients with smaller lesions, EUS-guided sampling was 100% in very small (less than 11 mm) and extremely small lesions (less than 8 mm). The biopsy success rate was 100% in tail lesions in the size range between ≥5.95 and <8.1 mm but only 33.3% independent of the investigator in pancreatic head or body, with an error rate of 11.2% CONCLUSION: Using a recursive partitioning of the tree-aided stratification model, we demonstrate for the first time that in balancing risks and benefits, very small pNETs (<1 cm) in the tail of the pancreas should be sampled under EUS-guidance.

Antitumoral Activity of the MEK Inhibitor Trametinib (TMT212) Alone and in Combination with the CDK4/6 Inhibitor Ribociclib (LEE011) in Neuroendocrine Tumor Cells In Vitro.

OBJECTIVES: This study assessed the antitumoral activity of the MEK inhibitor trametinib (TMT212) and the ERK1/2 inhibitor SCH772984, alone and in combination with the CDK4/6 inhibitor ribociclib (LEE011) in human neuroendocrine tumor (NET) cell lines in vitro. METHODS: Human NET cell lines BON1, QGP-1, and NCI-H727 were treated with trametinib or SCH772984, alone and in combination with ribociclib, to assess cell proliferation, cell cycle distribution, and protein signaling using cell proliferation, flow cytometry, and Western blot assays, respectively. RESULTS: Trametinib and SCH772984, alone and in combination with ribociclib, significantly reduced NET cell viability and arrested NET cells at the G1 phase of the cell cycle in all three cell lines tested. In addition, trametinib also caused subG1 events and apoptotic PARP cleavage in QGP1 and NCI-H727 cells. A western blot analysis demonstrated the use of trametinib alone and trametinib in combination with ribociclib to decrease the expression of pERK, cMyc, Chk1, pChk2, pCDK1, CyclinD1, and c-myc in a time-dependent manner in NCI-H727 and QGP-1 cells. CONCLUSIONS: MEK and ERK inhibition causes antiproliferative effects in human NET cell lines in vitro. The combination of the MEK inhibitor trametinib (TMT212) with the CDK4/6 inhibitor ribociclib (LEE011) causes additive antiproliferative effects. Future preclinical and clinical studies of MEK inhibition in NETs should be performed.

Feasibility and Early Clinical Experience of Online Adaptive MR-Guided Radiotherapy of Liver Tumors.

PURPOSE: To assess the feasibility and early results of online adaptive MR-guided radiotherapy (oMRgRT) of liver tumors. METHODS: We retrospectively examined consecutive patients with primary or secondary liver lesions treated at our institution using a 0.35T hybrid MR-Linac (Viewray Inc., Mountain View, CA, USA). Online-adaptive treatment planning was used to account for interfractional anatomical changes, and real-time intrafractional motion management using online 2D cine MRI was performed using a respiratory gating approach. Treatment response and toxicity were assessed during follow-up. RESULTS: Eleven patients and a total of 15 lesions were evaluated. Histologies included cholangiocarcinomas and metastases of neuroendocrine tumors, colorectal carcinomas, sarcomas and a gastrointestinal stroma tumor. The median BED10 of the PTV prescription doses was 84.4 Gy (range 59.5-112.5 Gy) applied in 3-5 fractions and the mean GTV BED10 was in median 147.9 Gy (range 71.7-200.5 Gy). Online plan adaptation was performed in 98% of fractions. The median overall treatment duration was 53 min. The treatment was feasible and successfully completed in all patients. After a median follow-up of five months, no local failure occurred and no ≥ grade two toxicity was observed. OMRgRT resulted in better PTV coverage and fewer OAR constraint violations. CONCLUSION: Early results of MR-linac based oMRgRT for the primary and secondary liver tumors are promising. The treatment was feasible in all cases and well tolerated with minimal toxicity. The technique should be compared to conventional SBRT in further studies to assess the advantages of the technique.

Mixed large cell neuroendocrine carcinoma and squamous cell carcinoma of the colon: detailed molecular characterisation of two cases indicates a distinct colorectal cancer entity.

We present two rare cases of mixed large cell neuroendocrine carcinoma and squamous cell carcinoma of the colon. A literature search revealed only three published cases with similar histology but none of these reports provided profound molecular and mutational analyses. Our two cases exhibited a distinct, colon-like immunophenotype with strong nuclear CDX2 and ß-catenin expression in more than 90% of the tumour cells of both components. We analysed the two carcinomas regarding microsatellite stability, RAS, BRAF and PD-L1 status. In addition, next-generation panel sequencing with Ion AmpliSeq™ Cancer Hotspot Panel v2 was performed. This approach revealed mutations in FBXW7, CTNNB1 and PIK3CA in the first case and FBXW7 and RB1 mutations in the second case. We looked for similar mutational patterns in three publicly available colorectal adenocarcinoma data sets, as well as in collections of colorectal mixed neuroendocrine-non-neuroendocrine neoplasms (MiNENs) and colorectal neuroendocrine carcinomas. This approach indicated that the FBXW7 point mutation, without being accompanied by classical adenoma-carcinoma sequence mutations, such as APC, KRAS and TP53, likely occurs at a relatively high frequency in mixed neuroendocrine and squamous cell carcinoma and therefore may be characteristic for this rare tumour type. FBXW7 codifies the substrate recognition element of an ubiquitin ligase, and inactivating FBXW7 mutations lead to an exceptional accumulation of its target ß-catenin which results in overactivation of the Wnt-signalling pathway. In line with previously described hypotheses of de-differentiation of colon cells by enhanced Wnt-signalling, our data indicate a crucial role for mutant FBXW7 in the unusual morphological switch that determines these rare neoplasms. Therefore, mixed large cell neuroendocrine and a squamous cell carcinoma can be considered as a distinct carcinoma entity in the colon, defined by morphology, immunophenotype and distinct molecular genetic alteration(s).

Inhibition of Wnt/ß-Catenin Signaling in Neuroendocrine Tumors in vitro: Antitumoral Effects.

BACKGROUND AND AIMS: Inhibition of Wnt/ß-catenin signaling by specific inhibitors is currently being investigated as an antitumoral strategy for various cancers. The role of Wnt/ß-catenin signaling in neuroendocrine tumors still needs to be further investigated. METHODS: This study investigated the antitumor activity of the porcupine (PORCN) inhibitor WNT974 and the ß-catenin inhibitor PRI-724 in human neuroendocrine tumor (NET) cell lines BON1, QGP-1, and NCI-H727 in vitro. NET cells were treated with WNT974, PRI-724, or small interfering ribonucleic acids against ß-catenin, and subsequent analyses included cell viability assays, flow cytometric cell cycle analysis, caspase3/7 assays and Western blot analysis. RESULTS: Treatment of NET cells with WNT974 significantly reduced NET cell viability in a dose- and time-dependent manner by inducing NET cell cycle arrest at the G1 and G2/M phases without inducing apoptosis. WNT974 primarily blocked Wnt/ß-catenin signaling by the dose- and time-dependent downregulation of low-density lipoprotein receptor-related protein 6 (LRP6) phosphorylation and non-phosphorylated ß-catenin and total ß-catenin, as well as the genes targeting the latter (c-Myc and cyclinD1). Furthermore, the WNT974-induced reduction of NET cell viability occurred through the inhibition of GSK-3-dependent or independent signaling (including pAKT/mTOR, pEGFR and pIGFR signaling). Similarly, treatment of NET cells with the ß-catenin inhibitor PRI-724 caused significant growth inhibition, while the knockdown of ß-catenin expression by siRNA reduced NET tumor cell viability of BON1 cells but not of NCI-H727 cells. CONCLUSIONS: The PORCN inhibitor WNT974 possesses antitumor properties in NET cell lines by inhibiting Wnt and related signaling. In addition, the ß-catenin inhibitor PRI-724 possesses antitumor properties in NET cell lines. Future studies are needed to determine the role of Wnt/ß-catenin signaling in NET as a potential therapeutic target.

[The Thyroid and Pregnancy]. / Schilddrüse und Schwangerschaft.

Pregnancy has a profound impact on the thyroid gland and its function. This has to be considered in the assessment of thyroid function tests on the basis of trimester-specific reference intervals during pregnancy and in the decision making when to start therapy.The adverse impact of overt thyroid disorders in pregnancy is well understood, while the relevance of subclinical thyroid disorders and presence of thyroid antibodies remains a bit controversial. In euthyroid pregnant women with positive thyroid antibodies, levothyroxine (LT4) therapy may be discussed individually in the case of recurrent abortions. Furthermore, the risk of adverse pregnancy outcomes seems to be increased in the presence of both thyroid-stimulating hormone (TSH)-elevation and positive thyroid antibodies. Therefore, in case of subclinical hypothyroidism, taking in consideration the thyroid peroxidase antibody (TPO-Ab)-status individual decision-making and liberal initiation of LT4 therapy is recommended. In contrast, overt hypothyroidism is a strong indication for LT4 administration, aiming at rapid achievement of euthyroidism.The most common cause of hyperthyroidism is transient gestational thyrotoxicosis mediated by human chorionic gonadotropin (hCG), which leads to a reduction or suppression of TSH in the first trimester that does not require antithyroid medication. In other causes of overt hyperthyroidism antithyroid drugs (propylthiouracil or thionamides) need to be considered carefully and require interdisciplinary management.The presented recommendations are based on the current guideline of the American Thyroid Association (ATA) and the European Thyroid Association (ETA) as well as recently published literature.

[Current standards and novel developments in the treatment of neuroendocrine tumors of the gastroenteropancreatic system]. / Neues zur Therapie von neuroendokrinen Tumoren des gastroenteropankreatischen Systems.

Current guidelines have been published for the diagnosis and therapy of neuroendocrine neoplasms of the gastroenteropancreatic (GEP) system 1. Systemic therapy of inoperable advanced neuroendocrine tumors includes biotherapy with somatostatin analogas, peptid receptor radionuclide therapy (PRRT) with 177Lutetium-DOTA-TATE, chemotherapy with steptozotocin/5-fluorouracil or capecitabine/temozolomide and molecular targeted therapy with everolimus or sunitinib 1 2. For symptom control in patients with carcinoid syndrome biotherapy with somatostatin analogs, PRRT, loco-regional and local-ablative interventional procedures of liver metastases as well as the peripheral serotonin synthesis inhibitor telotristat Ethyl 1 2 3 4 are highly effective. Novel aspects and developments in the diagnosis and treatment of neuroendocrine tumors will be discussed in this review.

The Novel Cyclin-Dependent Kinase 4/6 Inhibitor Ribociclib (LEE011) Alone and in Dual-Targeting Approaches Demonstrates Antitumoral Efficacy in Neuroendocrine Tumors in vitro.

BACKGROUND/AIM: Cyclin-dependent kinases (CDKs) are crucial for cell cycle regulation, and alterations in the cell cycle are often observed in human cancer. CDK4/6 in particular orchestrates G1 phase progression and the G1/S transition. Here, we investigated the in vitro effects of the CDK4/6 inhibitor LEE011 in human neuroendocrine tumor cells. METHODS: The human neuroendocrine tumor cell lines BON1, QGP1, NCI-H727 and GOT1 were treated with different concentrations of LEE011 alone and in combination with 5-fluorouracil and everolimus. RESULTS: Cell viability decreased in a time- and dose-dependent manner in BON1, QGP1, and NCI-H727 cells upon LEE011 treatment, whereas GOT1 cells were treatment resistant. Treatment sensitivity towards LEE011 was associated with the high expression of cyclin D1 and Rb. LEE011 caused the dephosphorylation of Rb and a subsequent G1 phase cell cycle arrest. Combined treatment with LEE011 and 5-fluorouracil or everolimus showed a significant enhancement in the inhibition of cell viability when compared to single-substance treatments due to PI3K-Akt-mTOR and Ras-Raf-MEK-ERK pathway downregulation and cooperative downregulation of cell cycle components. However, LEE011 also exhibited antagonizing effects with 5-fluorouracil, protecting NET cells from DNA-damaging chemotherapy by blocking PARP cleavage and caspase-3/7 activity. CONCLUSIONS: Our data demonstrate that the CDK 4/6 inhibitor LEE011 exhibits promising anti-tumoral properties alone and in combination treatment approaches with 5-fluorouracil or everolimus in human neuroendocrine tumor cell lines.

GSK3α/ß: A Novel Therapeutic Target for Neuroendocrine Tumors.

INTRODUCTION: Glycogen synthase kinase 3α/ß (GSK3α/ß) is a serine/threonine kinase that plays a critical role in cancer. AIMS: In this study, we evaluated the effects of the specific GSK3α/ß inhibitor AR-A014418 in vitro to gain novel insights into GSK3α/ß signaling in neuroendocrine tumors (NETs). MATERIALS AND METHODS: Human NET cell lines (BON1, QGP1, H727, and GOT1) were treated with different concentrations of AR-A014418 alone and in combination with lovastatin, everolimus, 5-fluorouracil (5-FU), and γ-irradiation. RESULTS: AR-A014418 significantly dose- and time-dependently decreased cell viability in all 4 NET cell lines through inhibition of epithelial growth factor receptor and mTORC1/p70S6K signaling, as well as cyclin D3 downregulation and induction of pChk1. In all cell lines tested, FACS analysis showed an AR-A014418-induced increase in the sub-G1 phase, reflecting cell death. Apoptosis induction was observed in H727, GOT1 and QGP1 cells, but not in BON1 cells. Furthermore, significant antimigratory effects upon GSK3α/ß inhibition were found and were associated with ß-catenin downregulation in all cell lines tested. Compensatory upregulation of pAkt and pERK in response to GSK3α/ß inhibition was prevented by combining AR-A014418 with the ERK and Akt inhibitor lovastatin. Accordingly, the lovastatin/AR-A014418 combination was synergistic in BON1 and QGP1 cells. Moreover, AR-A014418 displayed promising chemosensitizing effects on 5-FU in QGP1 and slight radiosensitizing properties in BON1 and QGP1 cells. CONCLUSION: Our data provide new insights into the role of GSK3α/ß in NETs and suggest that GSK3α/ß inhibition could be a novel therapeutic option in NETs, especially in combination with lovastatin or 5-FU, depending on tumor entity.