PI3K-AKT-mTOR-signaling and beyond: the complex network in gastroenteropancreatic neuroendocrine neoplasms.
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ABSTRACT:
SUBMITTER: Briest F
PROVIDER: S-EPMC3936289 | biostudies-literature | 2014
REPOSITORIES: biostudies-literature
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PI3K-AKT-mTOR-signaling and beyond: the complex network in gastroenteropancreatic neuroendocrine neoplasms.
Briest Franziska F Grabowski Patricia P
Theranostics 20140129 4
Gastroenteropancreatic neuroendocrine neoplasms are heterogeneous in their clinical behavior and require therapies specially tailored according to staging, grading, origin and expression of peptide receptors. Despite extensive scientific efforts, the therapy options are still not satisfactory. The main reasons are due to the lack of a broad mechanistic knowledge, an insufficient classification of specific diagnostic sub-groups, and predictive markers. GEP-NEN tumors evade early diagnosis because ...[more]
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Project description:PurposeGEP-NENs are rare malignancies with increasing incidence. Their molecular characteristics are still undefined. We explored the underlying biology of GEP-NENs and the differences between gastrointestinal (GI) and pancreatic (PNEN), high-grade (HG), and low-grade (LG) tumors.Experimental designGEP-NENs were analyzed using next-generation sequencing (NGS; MiSeq on 47 genes, NextSeq on 592 genes), IHC, and in situ hybridization. Tumor mutational burden (TMB) was calculated on the basis of somatic nonsynonymous missense mutations, and microsatellite instability (MSI) was evaluated by NGS of known MSI loci.ResultsIn total, 724 GEP-NENs were examined: GI (N = 469), PNEN (N = 255), HG (N = 135), and LG (N = 335). Forty-nine percent were female, and median age was 59. Among LG tumors, the most frequently mutated genes were ATRX (13%), ARID1A (10%), and MEN1 (10%). HG tumors showed TP53 (51%), KRAS (30%), APC (27%), and ARID1A (23%). Immune-related biomarkers yielded a lower prevalence in LG tumors compared with HG [MSI-H 0% vs. 4% (P = 0.04), PD-L1 overexpression 1% vs. 6% (P = 0.03), TMB-high 1% vs. 7% (P = 0.05)]. Compared with LG, HG NENs showed a higher mutation rate in BRAF (5.4% vs. 0%, P < 0.0001), KRAS (29.4% vs. 2.6%, P < 0.0001), and PI3KCA (7% vs. 0.3%, P < 0.0001). When compared with GI, PNEN carried higher frequency of MEN1 (25.9% vs. 0.0%, P < 0.0001), FOXO3 (8.6% vs. 0.8%, P = 0.005), ATRX (20.6% vs. 2.0%, P = 0.007), and TSC2 (6.3% vs. 0.0%, P = 0.007), but lower frequency of mutations in APC (1.0% vs. 13.8%, P < 0.0001).ConclusionsSignificant molecular differences were observed in GEP-NENs by tumor location and grade, indicating differences in carcinogenic pathways and biology.
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Project description:BackgroundGrade 3 gastroenteropancreatic neuroendocrine neoplasms (G3 GEPNENs) are often aggressive, and the optimal treatment is unclear for this subgroup of neuroendocrine neoplasms (NENs). Temozolomide (TEM)-based regimens have been increasingly used to treat grade 1-2 NENs, but their efficacy in G3 NENs remains undetermined. We aimed to assess the clinical efficacy of TEM-containing regimens in advanced grade 3 GEPNENs.Materials and methodsA multicenter retrospective review (2008-2018) of patients with metastatic/unresectable G3 GEPNENs who received a TEM-containing regimen was undertaken within a North American partnership to pool data. The primary endpoint was time to treatment failure (TTF). Radiologic response was extracted from local reports.ResultsOne hundred and thirty patients in six high-volume NEN centers were included (median age 55, 64% male, 18% functional, 67% pancreatic NEN). Forty-nine percent were well-differentiated, 35% poorly differentiated, and 15% unknown based on local pathology reports. The regimen used was capecitabine and temozolomide (CAPTEM) in 92% and TEM alone in 8%. Radiological response by local assessment was seen in 36% of patients. Median TTF was 3.6 months and median overall survival (OS) 19.2 months. Six percent of patients required discontinuation of therapy due to adverse events. TTF was longer in first-line treatment (7.8 months vs. 2.9 months; hazard ratio, 1.62; 95% confidence interval, 1.11-2.36; p = .015) and in patients with pancreatic NENs (panNENs) compared with gastrointestinal NENs (5.8 months vs 1.8 months; p = .04). The overall response rate was higher in the first-line setting (51% vs 29%; p = .02) and in panNEN (41% vs 23%; p = .04).ConclusionThis is the largest TEM treatment series in G3 NEN, involving collaboration of several major North American NEN centers as a partnership. Thirty-six percent of patients showed some degree of radiographic response, and treatment was generally well tolerated, although the median duration of response was short. Response rates and time to treatment failure were superior in the first-line setting. CAPTEM should be considered a viable treatment option in this setting. Further randomized trials are warranted.Implications for practiceNeuroendocrine neoplasms (NENs) are heterogeneous, and optimal treatment for aggressive grade 3 (G3) NENs remains undetermined. The capecitabine and temozolomide (CAPTEM) regimen has been used in low-grade pancreas NENs but there are few data for its safety and efficacy in the G3 setting. This article reports on the efficacy of temozolomide-containing regimens, particularly CAPTEM, in management of G3 NENs. The good tolerance and response rate show that CAPTEM should be considered a viable regimen in treatment of G3 NENs pending confirmatory prospective studies.
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