Abstract
c-Myc is an oncogene that is dysregulated in various cancers. Early gastric neoplasia with c-Myc expression has been reported as a more malignant lesion. This study clarifies the differences in c-Myc expression in early gastric neoplasia based on the WHO classification. Samples from 100 patients with differentiated-type early gastric neoplasia, who underwent endoscopic submucosal dissection between March 2020 and January 2021, were stained for c-Myc. One hundred lesions were classified as low-grade dysplasia, high-grade dysplasia, or intramucosal adenocarcinoma. The staining intensity and extent were scored. A hierarchical cluster analysis for a clinicopathological analysis among the groups, the chi-square test, Bonferroni correction, and residual analysis were performed. Subgroup one and two consisted of 39 patients; while subgroup three consisted of 22. Significant differences among various characteristics were observed between these subgroups. The frequency of low-grade dysplasia was significantly higher, while that of high-grade dysplasia was significantly lower in subgroup three. The frequency of intramucosal adenocarcinoma was significantly higher in subgroup one. The c-Myc positivity rate was significantly higher in subgroup one compared with that in subgroup three. c-Myc expression distinctly differed in early gastric neoplasia. c-Myc-negative low-grade dysplasia may be separately categorized from c-Myc-positive low-grade dysplasia, high-grade dysplasia, and intramucosal adenocarcinoma.
Highlights
We evaluated 107 patients who underwent endoscopic submucosal dissection at the Department of Gastroenterology, Takeda General Hospital, between March 2020 and January 2021, and were diagnosed with differentiated-type early gastric neoplasia based on histopathological examination
In terms of the invasion depth, the frequency of T1a was higher in low-grade dysplasia (LGD) (100%) and that of T1b was higher in intramucosal adenocarcinoma (IMA) (25%)
In terms of the gross morphology, the elevated type was more frequent in LGD (70.8%), the mixed type was more frequent in high-grade dysplasia (HGD) (11.1%), and the depressed type was more frequent in IMA (87.5%) (p < 0.01)
Summary
The use of a genetic analysis to clarify the molecular pathogenesis of gastric cancer has greatly increased in recent years [1]. In Japan, an intramucosal adenocarcinoma (IMA), and low-grade dysplasia (LGD) and high-grade dysplasia (HGD) are targeted for resection. A gain in c-Myc (8q24.21) is a genetic abnormality that occurs in the early stage of the disease and may be a driver gene [3]. The CNA analysis of 84 cases of gastric intramucosal epithelial tumors showed that the frequency of 8q gain was increased in HGD and IMA rather than in LGD [4]. The gain of a gene has been reported to correlate with an increased protein expression [5]
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