Myeloid, B and T lymphoid and mixed lineage thymic lymphomas in the irradiated mouse.
Thymic lymphoma is a very common spontaneous and/or induced malignancy in both inbred mice and in transgenic mouse models of human cancer. Although a thymic lymphoma is defined as thymus-dependent T-cell malignancy, diagnostic criteria vary between studies and considerable heterogeneity has been reported. To define and classify the thymic lymphomas that arose in our study of X-irradiated (CBA/HxC57BL/6)F1, F1 backcross and F1 intercross mice, 66 thymic lymphomas were immunogenotyped for immunoglobulin heavy chain (IgH) and T-cell receptor beta (TCRbeta) gene rearrangements, and/or analysed for expression of lineage-specific markers and allelic loss on chromosome 4. The data indicate that 33% of the thymic lymphomas are very similar to mouse radiation-induced acute myeloid (AML) and mixed lineage (IgH(R), TCRbeta(G)) pre-B lympho-myeloid (L-MLs) leukaemias, 33% are mixed lineage (IgH(R), TCRbeta(R)) B/T lymphoid and <33% can be described as single lineage (IgH(G), TCRbeta(R)) T-cell malignancies. As the myeloid and L-ML leukaemias are not thymus-dependent this suggests that a malignant myeloid or pre-B lympho-myeloid cell can colonize the spleen to give an AML or L-ML leukaemia, or can colonize the thymus where TCRbeta gene rearrangement(s) may be induced to give the mixed lineage thymic lymphomas. Thus, assuming the single lineage T-cell thymic lymphomas fulfil the criteria of a thymus-dependent T-cell malignancy, thymic lymphomas are comprised of at least three distinct malignancies.
Boulton
Emma
E
MRC Radiation and Genome Stability Unit, Chilton Didcot, Oxfordshire OX11 ORD, UK.
Cleary
Helen
H
Plumb
Mark
M
D000818:Animals; D001402:B-Lymphocytes / Q000276:immunology* / Q000473:pathology; D002872:Chromosome Deletion; D003433:Crosses, Genetic; D015322:Gene Rearrangement, B-Lymphocyte; D005819:Genetic Markers; D005838:Genotype; D019656:Loss of Heterozygosity; D008223:Lymphoma / Q000235:genetics* / Q000276:immunology; D016393:Lymphoma, B-Cell / Q000235:genetics / Q000276:immunology; D016399:Lymphoma, T-Cell / Q000235:genetics / Q000276:immunology; D051379:Mice; D008810:Mice, Inbred C57BL; D008808:Mice, Inbred CBA; D009381:Neoplasms, Radiation-Induced / Q000235:genetics / Q000276:immunology*; D013601:T-Lymphocytes / Q000276:immunology* / Q000473:pathology; D013953:Thymus Neoplasms / Q000235:genetics* / Q000276:immunology; D014965:X-Rays
D005819:Genetic Markers