Comprehensive mutational analysis of background mucosa in patients with Lugol‐voiding lesions

Abstract

Somatic mutations including the background mucosa in patients with Lugol‐voiding lesions (LVLs) are still not well known. The aim of this study was to evaluate the somatic mutations of the background mucosa in patients with LVLs (Squamous cell carcinoma (SCC), intraepithelial neoplasia (IN), and hyperplasia). Twenty‐five patients with LVLs (9 with SCC, 6 with IN, and 10 with hyperplasia) were included. A targeted sequence was performed for LVLs and background mucosa using an esophageal cancer panel. Each mutation was checked whether it was oncogenic or not concerning OncoKB. In LVLs, TP53 was the most dominant mutation (80%). Furthermore, 72% of TP53 mutations was putative drivers. In background mucosa, NOTCH1 was the most dominant mutation (88%) and TP53 was the second most dominant mutation (48%). Furthermore, 73% of TP53 mutations and 8% of NOTCH1 mutations were putative drivers. Putative driver mutations of TP53 had significantly higher allele frequency (AF) in SCC than in IN and hyperplasia. Conversely, putative driver mutations of NOTCH1 did not have a significant accumulation of AF in the progression of carcinogenesis. Furthermore, in SCC, AF of TP53 mutations was significantly higher in LVLs than in background mucosa, but not in IN and hyperplasia. Regarding NOTCH1, a significant difference was not observed between LVLs and background mucosa in each group. The background mucosa in patients with LVLs already had putative driver mutations such as TP53 and NOTCH1. Of these two genes, TP53 mutation could be the main target gene of carcinogenesis in esophageal SCC. Clinical Trials registry: UMIN000034247.

Carcinogenic potential in regenerated mucosa after endoscopic resection of esophageal squamous cell carcinoma

“…On the other hand, NOTCH1 mutations were less common in ESCC. 16,17 This result was observed in several studies; moreover, our study also revealed more NOTCH1 mutations in RM and BM than in SCC. These results suggest that NOTCH1 mutations may not be directly involved in carcinogenesis.…”

“…Targeted next-generation sequencing. The extracted DNA was amplified by multiplex polymerase chain reaction (PCR) with the premixed EC panel used previously 17 and Ion AmpliSeq HiFi Master Mix (Ion AmpliSeq Library Kit 2.0; Thermo Fisher Scientific). After multiplex PCR, the amplicons were treated with FuPa Reagent (Ion AmpliSeq Library Kit 2.0) to partially digest the primer sequences and phosphorylate the amplicons to optimize the sequencing performance.…”

“…This analysis method was as previously performed. 17 We used OncoKB (http://oncokb.org/) to analyze each mutant gene to determine whether or not the mutation was a putative driver. Oncogenic and likely oncogenic mutations were defined as putative driver mutations.…”

“…[13][14][15] Additionally, recent studies reported that the background mucosa (BM) in patients with a risk factor for ESCC contains various genetic mutations. 16,17 On the other hand, the occurrence of genetic mutations in the regenerated mucosa (RM) after ER remains unknown. The identification of such mutations may provide new insights into the prevention and posttreatment surveillance of ESCC.…”

“…Field cancerization, in which various carcinogens affect the esophageal epithelium and the esophagus has carcinogenic potential as a whole, is an accepted concept in ESCC 13–15 . Additionally, recent studies reported that the background mucosa (BM) in patients with a risk factor for ESCC contains various genetic mutations 16,17 …”