Dear usluceren, C-erb-B2 is another name for the Her-2 neu protein that is found on the surface of some breast cancers. A breast cancer that is Her2 neu positive may be more likely to recur.
This information along with the other information such as staging, tumor characteristics (ER status, Her2 status), help to determine the recommendations regarding treatments. However, it is impossible to predict for sure how an individual is going to do. What is hoped is that the adjuvant chemotherapy will do its job in terms of eliminating any microscopic disease that may be present in the body after the primary tumor is removed, and that the tamoxifen then decreases the hormonal climate by blocking estrogen that may have contributed to cancer growth.
There is a good essay written that helps to put the issue of cancer statistics into perspective on the National Alliance of Breast Cancer Organizations (NABCO) website. I am including the direct link to the article here: http://www.nabco.org/index.php/index.php/138