Genetics of urinary bladder paragangliomas: a multi-center study of a Chinese cohort.

Purpose: 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.

Methods: 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.

Results: 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.

Conclusion: 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.