http://www.nsabp.pitt.edu/cMYC_Press_Release_121505.pdf
Sorry, I can't copy from the pdf, but basically herceptin-based chemo seems to reduce the risk of recurrence by twice as much in women with cmyc+ breast cancer (76%) versus cmyc- breast cancer (37%). There were no recurrences after two years in the cmyc amplified patients herceptin-treated patients. This reverses the worse prognosis of cmyc+ patients, perhaps because cmyc and her2 work together to worsen the prognosis.