Hi, I googled "triple negative breast cancer metaplastic", and came up with some very clear and helpful material. There is one article http://www.nature.com/onc/journal/vaop/ncurrent/abs/1210014a.html that is very medical but explains it, that metaplastic is a rarer type of basal-like tumors.
Did the docs try to support your WBC with Neulastin, or something like that? It sucks to have to get off a good tx because of #'s.
There were lots of articles and other resources if you google like I did. That's all I know. Good luck, my dear.