👤 Karel Pacak

Pheochromocytoma and paraganglioma (together PPGL) are tumours with a high degree of heritability. Genetic landscape is divided into three clusters, cluster 1 (Krebs/pseudohypoxia signalling pathway), cluster 2 (kinase signalling pathway) and cluster 3 (Wnt signalling pathway). With increasing knowledge in the field of genetics, cluster-specific tumour characteristics, biochemical phenotype and imaging signatures are established in commonly found genes. The association of FGFR1 pathogenic mutations with PPGL have been recently described although its features are not yet well established. Here, we present four patients with PPGL who were found to have somatic FGFR1 pathogenic mutations. We discuss their clinical presentations, biochemical phenotypes, imaging signatures and treatment options that will be relevant for practicing physicians in managing these patients effectively. Show less

Pheochromocytomas and paragangliomas (PPGLs) exhibit the highest degree of heritability among all human tumors, yet the genetics of urinary bladder paragangliomas (UBPGLs) remains poorly understood. The present study aims to examine the characteristics of a cohort of Chinese patients with UBPGLs, focusing particularly on genetics. The study included 70 Chinese patients with UBPGLs from 15 centers in China, 240 patients with non-head and neck PGLs (non-HNPGLs) outside the urine bladder, and 16 Caucasian patients with UBPGLs. Tumor DNA samples were sequenced by next generation sequencing. All identified pathogenic variants (PVs) were confirmed by Sanger sequencing. Among the 70 Chinese patients, PVs were identified in 38 cases: 23 in cluster 1 A (13 SDHB, 1 SDHD, 1 SDHA, 4 IDH1, 2 SLC25A11, and 2 FH), 4 in cluster 1B (3 EPAS1 and 1 EGLN1), and 11 in cluster 2 genes (7 HRAS, 1 FGFR1, 2 NF1, and 1 H3F3A). Compared with other non-HNPGLs, UBPGLs had more PVs in cluster 1 A genes (32.9% vs. 14.2%, p < 0.001), but fewer in cluster 1B (5.7% vs. 19.2%, p = 0.002) and cluster 2 genes (15.7% vs. 42.5%, p < 0.001). PVs in SDHB (18.6%) was the most common in Chinese patients with UBPGLs, followed by HRAS (10.0%). No PVs was found in 45.7% of all UBPGLs. PVs in HRAS, SLC25A11, EPAS1, and FH were also identified in Caucasians with UBPGLs. Chinese patients with UBPGLs have a diverse genetic profile. PVs in cluster 1 A genes underlie nearly 1/3 of patients, highlighting the importance of genetic testing. Diverse germline and somatic PVs are also present in Caucasian patients with UBPGLs. Show less

Recurrent and metastatic pheochromocytoma (PCC) are rare advanced endocrine neoplasms with limited treatment options. Insight into the pathogenic molecular alterations in patients with advanced PCC can provide therapeutic options for precisely targeting dysregulated pathways. We report the discovery and characterization of a novel BRAF-containing fusion transcript and its downstream molecular alterations in a patient with recurrent PCC with peritoneal seeding (pheochromocytomatosis). We reviewed the medical record of a patient with pheochromocytomatosis. A comprehensive pan-cancer molecular profiling using next-generation sequencing (NGS) as well as confirmatory real-time-quantitative PCR were performed on surgical specimens. BRAF rearrangement and downstream molecular changes were assayed using fluorescence in situ hybridization (FISH) and immunohistochemistry (IHC), respectively. Western blot was used to assess the in vitro activation of the mitogen-activated protein kinase (MAPK) signaling pathway and the EMT markers in transfected HEK-293 cells. The NGS analysis of a specimen from a 72-year-old female patient with pheochromocytomatosis showed an in-frame fusion of exon 3 of Glucocorticoid Induced 1 (GLCCI1) to exon 9 of BRAF. The upstream auto-inhibitory domain of BRAF was excluded from the GLCCI1-BRAF fusion; however, the downstream BRAF kinase domain was intact. A BRAF rearrangement was confirmed via a BRAF-specific break-apart FISH assay. Four separate tumor foci harbored GLCCI1-BRAF fusion. IHC demonstrated increased phosphorylated MEK. HEK-293 cells transfected with the GLCCI1-BRAF fusion demonstrated increased phosphorylated MEK as well as higher expression of EMT markers SNAI1 and ZEB1 in vitro. We demonstrate a novel pathogenic gene fusion of GLCCI1 with the oncogenic kinase domain of BRAF, resulting in an activation of the MAPK signaling pathway and EMT markers. Thus, this patient may benefit from clinically available MEK and/or BRAF inhibitors when systemic therapy is indicated. This report is the first of GLCCI1 fused to BRAF in a human neoplasm and only the second BRAF-containing fusion transcript in PCC. Detailed molecular characterization of PCC can be a valuable tool in managing patients with recurrent PCC and pheochromocytomatosis that represents a significant clinical challenge. Show less

G We created mice (DMHGsKO) with G DMHGsKO mice developed severe, early-onset obesity associated with hyperphagia and reduced energy expenditure and locomotor activity, along with impaired brown adipose tissue thermogenesis. Studies in mice with loss of MC4R in the DMH suggest that defective DMH MC4R/G DMH G Show less