The DNA damage response protein p53-binding protein 1 (53BP1) accumulates and forms foci at double-strand DNA breaks, indicating the extent of DNA instability. However, the potential role of 53BP1 as a molecular biomarker for hypopharyngeal squamous cell carcinoma (HPSCC) diagnosis remains unknown. Here, we evaluated the potential of immunofluorescence-based analysis of 53BP1 expression to differentiate the histology of hypopharyngeal neoplasms. A total of 125 lesions from 39 surgically or endoscopically resected specimens from patients with HPSCC was histologically evaluated. 53BP1 expression in the nucleus was examined using immunofluorescence. The number of 53BP1 nuclear foci increased with the progression from non-tumorous to low-grade dysplasia, high-grade dysplasia, and squamous cell carcinoma. Unstable 53BP1 expression served as an independent factor for distinguishing lesions that required intervention. Colocalization of 53BP1 foci in proliferating cells, as assessed by Ki67, was increased in tumors ≥ 1000 µm in depth compared to those <1000 µm in depth at the tumor surface. Hence, the expression patterns of nuclear 53BP1 foci were associated with the progression of hypopharyngeal neoplasms. These findings suggest that 53BP1 could serve as an ancillary marker to support histological diagnosis and predict the factors that influence prognosis in patients with HPSCC.

The rarity of achalasia has led to limited opportunities for practical training in educational environments. Cadaver surgical training was developed to enhance surgical skills by providing physicians with experience comparable to that of on-the-job training using structures identical to living organs, thereby proving highly beneficial. Recently, cadavers have been preserved using the Thiel method, which maintains both mobility and organizational flexibility. However, there are few reports on therapeutic endoscopy, including peroral endoscopic myotomy, in the context of cadaver surgical training. We investigated the feasibility of using cadaver surgical training for therapeutic endoscopy training, termed Cadaver-based Therapeutic Endoscopy Training, for peroral endoscopic myotomy. This study was conducted in 2024 at the Cadaver Surgical Center of Nagasaki University using four cadavers preserved using the Thiel method. We performed peroral endoscopic myotomies on three cadavers and evaluated the observability of the esophageal mucosa, penetration of the local injection fluid, feasibility of creating a submucosal tunnel, visibility of indocyanine green injection, and inner circular muscle incision. The layered structure of the digestive tract was well preserved in the Thiel-fixed cadavers, and peroral endoscopic myotomy was performed without major issues. Cadaver-based Therapeutic Endoscopy Training may serve as a realistic training model comparable to living organs and may be beneficial for peroral endoscopic myotomy training.