title: Rearrangement of T-cell receptor beta and gamma genes in thymoma.
abstract: To investigate the differentiation stage of tumor-infiltrating lymphocytes in thymoma tissue, we performed Southern blot analysis of T-cell receptor beta and gamma genes in thymomas resected from 19 patients. At the same time, we conducted flow cytometric analysis of T-cell surface markers and examined the clinicopathological features of the thymomas. We found that the incidence of T-cell receptor gamma gene rearrangement was significantly higher in Masaoka stage I thymomas (11 of 12 cases) than in stage II or III invasive thymomas (3 of 7 cases). Moreover, gamma gene rearrangement was observed in all 10 type AB and B1 thymoma specimens and in 4 of 6 type B2 thymoma specimens. The 2 specimens of type B3 thymomas, which were classified as stage III, showed neither gamma nor beta gene arrangement and were single-positive for CD4 or CD8. Six thymoma specimens that showed beta gene rearrangement expressed both CD4 and CD8. In conclusion, thymomas have the capability of T-lineage cell differentiation, except for a subset of invasive thymomas with malignant characteristics.
authors.affiliation: Department of Cardiothoracic Surgery, Faculty of Medicine, University of Tokyo, Tokyo, Japan. nakajima-tho@h.u-tokyo.ac.jp
authors.forename: Jun
authors.initials: J
authors.lastname: Nakajima
authors.forename: Jun
authors.initials: J
authors.lastname: Matsumoto
authors.forename: Eriho
authors.initials: E
authors.lastname: Takeuchi
authors.forename: Takeshi
authors.initials: T
authors.lastname: Fukami
authors.forename: Shinichi
authors.initials: S
authors.lastname: Takamoto
mesh_terms: D000368:Aged; D015139:Blotting, Southern; D002454:Cell Differentiation; D005260:Female; D005434:Flow Cytometry; D015333:Gene Rearrangement, beta-Chain T-Cell Antigen Receptor / Q000502:physiology*; D015334:Gene Rearrangement, gamma-Chain T-Cell Antigen Receptor; D006801:Humans; D016246:Lymphocytes, Tumor-Infiltrating / Q000166:cytology*; D008297:Male; D008875:Middle Aged; D013945:Thymoma / Q000235:genetics*; D013953:Thymus Neoplasms / Q000235:genetics*