ASSESSING SEQUENTIAL ONCOGENE AMPLIFICATION IN HUMAN BREAST-CANCER

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.