CTNNB1 mutational analysis of solid-pseudopapillary neoplasms of the pancreas using endoscopic ultrasound-guided fine-needle aspiration and next-generation deep sequencing

Solid-pseudopapillary neoplasm (SPN), a rare neoplasm of the pancreas, frequently harbors mutations in exon 3 of the cadherin-associated protein beta 1 (CTNNB1) gene. Here, we analyzed SPN tissue for CTNNB1 mutations by deep sequencing using next-generation sequencing (NGS). Tissue samples from 7 SPNs and 31 other pancreatic lesions (16 pancreatic ductal adenocarcinomas (PDAC), 11 pancreatic neuroendocrine tumors (PNET), 1 acinar cell carcinoma, 1 autoimmune pancreatitis lesion, and 2 focal pancreatitis lesions) were analyzed by NGS for mutations in exon 3 of CTNNB1. A single-base-pair missense mutations in exon 3 of CTNNB1 was observed in all 7 SPNs and in 1 of 11 PNET samples. However, mutations were not observed in the tissue samples of any of the 16 PDAC or other four pancreatic disease cases. The variant frequency of CTNNB1 ranged from 5.4 to 48.8 %. Mutational analysis of CTNNB1 by NGS is feasible and was achieved using SPN samples obtained by endoscopic ultrasound-guided fine needle aspiration.