Genetic Instability and Apoptotic Cell Death during Neoplastic Progression of v-myc-initiated B-cell Lymphomas in the Bursa of Fabricius

Abstract

B-cell lymphoma arising in the bursa of Fabricius of chickens is both a naturally occurring neoplasm of commercial importance and an experimental system which has contributed significantly to knowledge about the role of retroviruses and oncogenes in tumorigenesis. The salient features of this tumor system have recently been reviewed (Neiman 1994). Briefly, the lymphoid population of embryonic follicles of the bursa is composed of large cycling lymphoblasts expressing surface IgM (Thompson et al. 1987). This population includes a stem-cell compartment of cells that can clonally reconstitute ablated bursal follicles in transplantation experiments (Pink et al. 1985). Deregulated expression of a myc oncogene within this stem-cell compartment, either due to integration of an avian leukosis virus (ALV) near c-myc (Hayward et al. 1981), or due to ex vivo infection of embryonic bursal lymphoblasts with a v-myc transducing avian myelocytomatosis virus (Neiman et al. 1985; Thompson et al. 1987), initiates neoplastic change...