Radiation evaluation assay using a human three-dimensional oral cancer model for clinical radiation therapy.

With the development of various radiation-based cancer therapies, radiobiological evaluation methods instead of traditional clonogenic assays with monolayer single cell culture are required to bridge gaps in clinical data. Heterogeneity within cancer tissues is the reason for bridging the gap between basic and clinical research in cancer radiotherapy. To solve this problem, we investigated an evaluation assay using a three-dimensional (3D) model of cancer tissue. In this study, a 3D model consisting of tumor and stromal layers was used to compare and verify radiobiological effects with conventional two-dimensional (2D) methods. A significant difference in the response to radiation was observed between the 2D and 3D models. The relative number of cancer cells decreased with X-ray dose escalations in the 2D and 3D models. In contrast, the relative number of normal cells was quite different between the 2D and 3D models. Considering the ability of cells to recover from radiation-induced damage, the histological results of the 3D model were reflected in the clinical data. Histopathological analysis using a 3D model is a potential method for evaluating radiobiological effects on the tumor and tumor margins.