Clinical Differences in c-Myc Expression in Early-Stage Gastric Neoplasia: A Retrospective Study Based on the WHO Classification.

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.