1. Neuroendocrine carcinoma and mixed neuroendocrine‒non-neuroendocrine neoplasm of the stomach: a clinicopathological and exome sequencing study
- Author
-
Masayuki Akita, Yoshihiro Kakeji, Yoh Zen, Hisayuki Matsumoto, Masato Komatsu, Jun Saegusa, Kohei Fujikura, Ryuichiro Sawada, Tomoo Itoh, and Sonoko Ishida
- Subjects
Male ,0301 basic medicine ,Pathology ,medicine.medical_specialty ,Adenocarcinoma ,Gene mutation ,Biology ,medicine.disease_cause ,Pathology and Forensic Medicine ,Frameshift mutation ,Loss of heterozygosity ,03 medical and health sciences ,0302 clinical medicine ,Stomach Neoplasms ,Exome Sequencing ,Biomarkers, Tumor ,medicine ,Humans ,Exome ,MEN1 ,Exome sequencing ,Aged ,Aged, 80 and over ,Molecular pathology ,Stomach ,Microsatellite instability ,Middle Aged ,medicine.disease ,digestive system diseases ,Carcinoma, Neuroendocrine ,Pancreatic Neoplasms ,Neuroendocrine Tumors ,030104 developmental biology ,030220 oncology & carcinogenesis ,Mutation ,KRAS - Abstract
Summary The gene mutation profiles of gastric neuroendocrine neoplasms are incompletely understood. The purpose of this study was to characterize the molecular pathology of poorly differentiated neuroendocrine carcinoma (NEC) and mixed neuroendocrine‒non-neuroendocrine neoplasm (MiNEN) of the stomach. Surgical cases of gastric NEC (n = 7) and MiNEN (n = 6) were examined by clinical review, immunohistochemistry, microsatellite instability (MSI) analysis and whole-exome sequencing. NEC cases consisted of small- (n = 2) and large-cell types (n = 4). All cases of MiNEN were histologically composed of large-cell type NEC and tubular adenocarcinoma. Whole-exome sequencing analysis detected recurrent mutations in TP53 in 8 cases (62%), and they were more frequently observed in MiNEN than in NEC (100% vs. 29%). Frameshift mutations of APC were observed in two cases of MiNEN. One case of large-cell type NEC had a frameshift mutation with loss of heterozygosity in RB1. The other mutated genes (e.g., ARID1 and KRAS) were detected in a single case each. A high level of MSI was confirmed in one case of MiNEN, which harbored mutations in two well-differentiated neuroendocrine tumor (NET)-related genes (MEN1 and ATRX1). In cases of MiNEN, two histological components shared mutations in TP53, APC and ZNF521, whereas alterations in CTNNB1, KMT2C, PTEN and SPEN were observed in neuroendocrine components only. In conclusion, TP53 is a single, frequently mutated gene in gastric NEC and MiNEN, and alterations in other genes are less common, resembling the mutation profiles of gastric adenocarcinomas. Gene mutations frequently observed in well-differentiated NET were uncommon but not entirely exclusive.
- Published
- 2021