Zhu, Wei Ping

The development and performance of two mass spectrometry (MS) workflows for the intraoperative diagnosis of isocitrate dehydrogenase (IDH) mutations in glioma is implemented by independent teams at Mayo Clinic, Jacksonville, and Huashan Hospital, Shanghai. The infiltrative nature of gliomas makes rapid diagnosis necessary to guide the extent of surgical resection of central nervous system (CNS) tumors. The combination of tissue biopsy and MS analysis used here satisfies this requirement. The key feature of both described methods is the use of tandem MS to measure the oncometabolite 2-hydroxyglutarate (2HG) relative to endogenous glutamate (Glu) to characterize the presence of mutant tumor. The experiments i) provide IDH mutation status for individual patients and ii) demonstrate a strong correlation of 2HG signals with tumor infiltration. The measured ratio of 2HG to Glu correlates with IDH-mutant (IDH-mut) glioma ( P < 0.0001) in the tumor core data of both teams. Despite using different ionization methods and different mass spectrometers, comparable performance in determining IDH mutations from core tumor biopsies was achieved with sensitivities, specificities, and accuracies all at 100%. None of the 31 patients at Mayo Clinic or the 74 patients at Huashan Hospital were misclassified when analyzing tumor core biopsies. Robustness of the methodology was evaluated by postoperative re-examination of samples. Both teams noted the presence of high concentrations of 2HG at surgical margins, supporting future use of intraoperative MS to monitor for clean surgical margins. The power of MS diagnostics is shown in resolving contradictory clinical features, e.g., in distinguishing gliosis from IDH-mut glioma.

SummaryObjectiveThymic neuroendocrine tumour (TH‐NET) accounts for almost 20% of multiple endocrine neoplasia type 1 (MEN1)‐associated mortality. Identifying risk factors for the development of these rare tumours and prognostic factors for clinical outcomes will be helpful in clinical practice.Design and PatientsWe performed a retrospective analysis of patients treated for TH‐NET associated with MEN1 in a single institution and meta‐analysis of literature reports. We used a fixed effect model to pool results across studies to evaluate the prevalence, clinical features and prognosis.ResultsTH‐NET was detected in 9 (7.4%) of 121 patients with MEN1 seen in our institution, and 5 (55.6%) were women. Seven additional studies were identified through a systematic review of the literature. The pool estimate of TH‐NET prevalence was 3.7% (n = 99) in MEN1 (n = 2710), sex ratio was 79:20 (male vs female), and the median age at diagnosis was 43.0 years (range, 16.0‐72.0 years). Forty‐three patients died with a median survival time of 8.4 years. Older age at diagnosis (HR = 1.4, 95% CI = 1.0‐1.8, P = .03), maximum tumour diameter (HR = 1.5, 95% CI = 1.0‐2.3, P = .04) and presence of metastasis (HR = 1.6, 95% CI = 1.0‐2.5, P = .04) were associated with worse outcome. A male predominance (91.9% vs 59.5%, P < .001) and history of smoking (59.0% vs 23.5%, P = .015) were more common in American/European series compared to Asian reports.ConclusionTH‐NET is a rare but fatal component of MEN1. Earlier detection of TH‐NET in patients with MEN1 may be recommended which should theoretically result in better outcomes. Different genetic backgrounds (race) appear to result in clinical difference.