Studies of amplification and/or overexpression of c-myc, HER-2/neu, an
d H-ras in breast cancer have shown that each is associated with a poo
r prognosis. The purpose of this study was to explore the possibility
that there is a preferred sequence of amplification of these oncogenes
in breast cancer, The frequencies of amplification and patterns of co
-amplification of c-myc, HER-2/neu, and H-ras were studied in a group
of 84 breast cancers, The data suggested a preferred sequence of ampli
fication that consisted of c-myc amplification-HER-2/neu amplification
-H-ras amplification, This model was supported by loglinear analysis,
In addition, the levels of amplification of JC-A, a DNA fragment newly
isolated from a patient with advanced breast cancer, were studied in
61 of these cases, The data suggested that JC-A amplification occurred
early. Loglinear analysis supported a model in which JC-A amplificati
on occurred either before or after c-myc amplification but was unrelat
ed to Her-2/neu or ras amplification. (C) 1995 Wiley-Liss, Inc.