A novel insight into the anticancer mechanism of metformin in pancreatic neuroendocrine tumor cells.

The antidiabetic drug metformin displays anticancer properties in several neoplasms. In pituitary NETs, aryl hydrocarbon receptor-interacting protein (AIP) is up-regulated by the somatostatin analog octreotide. Metformin inhibited QGP-1 cell proliferation in a dose- and time-dependent manner, at concentrations similar to those achievable in treated patients (-31 ± 12%, p < 0.05 vs basal at 100 µM). Moreover, metformin decreased pancreatic neuroendocrine tumors (PAN-NETs) cell proliferation (-62 ± 15%, p < 0.0001 vs basal at 10 mM), without any additive effect when combined with octreotide. Both octreotide and metformin induced AIP up-regulation. AIP silencing abolished the reduction of mTOR phosphorylation induced by metformin and octreotide. Moreover, metformin decreased HSP70, increased Zac1 and AhR expression; these effects were abolished in AIP silenced QGP-1 cells. In conclusion, metformin acts as an anticancer agent in PAN-NET cells, its activity is mediated by AIP and its interacting proteins. These findings provide a novel insight into the antitumorigenic mechanism of metformin.

Ampullary neuroendocrine neoplasms: surgical experience of a rare and challenging entity.

PURPOSE: Ampullary neuroendocrine neoplasms (NENs) account for < 0.3% of gastrointestinal NENs. Surgical options include transduodenal ampullectomy/tumour excision or pancreaticoduodenectomy (PD). We report the experience of two high-volume pancreatic surgical centres of ampullary NENs. METHODS: Clinical records of patients who underwent surgery for ampullary NENs (January 2007-November 2017) in the study centres were retrieved retrospectively. We evaluated clinical-pathological features, post-operative outcome and follow-up (FU). RESULTS: Eighteen patients (9 M/9 F, averaging 62 years) were enrolled. All but one were non-functioning NENs; four (22%) patients presented with jaundice. Seven (39%) of the patients underwent ampullectomy/excision (median tumour size 1.5 cm), and 11 (61%) patients underwent PD (median tumour size 2.4 cm). The median operation time of ampullectomy/excision was 221 min with operative blood loss of 75 ml (vs. 506 min and 425 ml in PD). The median hospital stay was 10 days in both groups. Overall surgical morbidity was 33%, due to four biochemical leaks, one pancreatic fistula and one abdominal haemorrhage. No reoperations were needed. The median tumour size was 1.8 (range 0.5-6.7) cm. All G2-G3 NENs were N1 (vs. 1/7 in G1 NENs). Three (17%) cases were mixed exocrine/G3 NECs. After a median FU of 45 (up to 124) months, recurrence occurred in four G3 NEC (31%) patients (median disease-free survival 14 months) after an R0 PD. Disease-related survival was 93, 77 and 66% at 1, 3 and 5 years, respectively. CONCLUSION: Ampullary NENs are mostly G1-G2 neoplasms. Lymph node metastases rarely occur in G1 NENs < 2 cm in size, which may be treated with ampullectomy/excision. Survival is 66% 5 years after surgery.

Technetium-99m -- new production and processing strategies to provide adequate levels for SPECT imaging.

The most important radioisotope for use in Nuclear Medicine is (99m)Tc, supplied in the form of a (99)Mo/(99m)Tc generator. After the supply crisis of (99)Mo starting in 2008 the availability of (99)Mo became a worldwide concern. The purpose of this work is to do a brief story of the availability of (99)Mo in the world followed by an overview of the production routes of (99)Mo and the generators technology.