Establishment and characterization of a novel cell line derived from type AB thymoma

Background: Thymoma has been recognized as the most prevalent tumor of anterior mediastinum. Nevertheless, due to the diverse classification of its subtypes and the absence of proper pre-clinical models, the therapeutic progress of thymoma has been hampered. Therefore, the present study reported the establishment and characterization of a novel human thymoma cell line, designated as T68, which may be useful for exploring the molecular and biological characteristics of thymoma. Methods: Thymoma cell line was derived from a male type AB patient aged 44 years. Furthermore, the morphology, growth rate and ultrastructure of this cell line, together with the expression of epithelial cell markers, were studied in this work. Morphology and immunohistochemical reactivity assays were conducted for the characterization of the established xenografts. Results: Thymoma cells grew and formed a monolayer in an adhering manner, with doubling time of 30 to 48 hrs. The ultrastructural analysis results revealed secretary vesicles and microfilaments, as well as the desmosomes and tight junctions. No reaction of the T68 cell line was observed to B-cell and T-cell lineage markers (e.g., TdT, CD5), while this cell line exhibited a more significant reaction to epithelial markers (e.g., CK8, CK18, CK19). The xenografted tumor was recognized as type AB thymoma. For the nude mice, the cell line exhibited tumorigenicity. In addition, the xenografts showed histologic characteristics that were comparable with the original tumor from which this cell line was derived. Conclusions: The established thymoma cell line and xenograft model proposed in this study is potential to be used for further multi-aspect studies of human thymoma biology and proposal of new treatment strategies.