Mycin chicks

Overexpression of the c-myc oncogene induces multistaged neoplastic progression leading to B-cell lymphomas in the bursa of Fabricius. In the May 22 Proceedings of the National Academy of Sciences, Neiman et al. describe the use of microarray analysis to define the genetic networks important for myc-induced lymphomagenesis (Proc Natl Acad Sci USA 2001, 98:6378-6383). The authors created a customized cDNA microarray containing over 2,200 genes associated with the immune system - details can be found on the Chick Website. They compared gene expression profiles of several stages of normal embryonic bursal development, myc-induced pre-neoplasic transformed follicles, metastatic lymphomas and the DT-40 lymphoma cell line. They found that a small subset of genes was differentially regulated during bursal differentiation, whereas hundreds of genes were influenced by c-myc expression. The best correlation between myc expression levels and gene induction was observed in pre-neoplastic follicles. Myc-induced genes include those involved with cell growth and energy control. The authors suggest that high levels of myc overexpression are more important for early lymphoma induction than for late-stage metastasis.