Jeanette I'm so sorry to hear about the mother with stage IV br cancer but she and you and ALL need to remember Breastfeeding CAN PREVENT and lessen the incidence of breast cancer in a population of women. Yes someone can develop breast cancer EVEN if she bf MANY children a LONG time, Because no one is sure when she developed the first genetic or cellular "seeds" of cancerous changes, (maybe even in child hood). In my humble opinion, the breastfeeding while it may have delayed the diagnosis and treatment of a cancer it MAY have also slowed the disease process down due to hormone suppression or immune boosting etc. she may have been given the chance to breastfeed her children BECAUSE she breastfed ! only "our higher power" knows for sure.....NOT breastfeeding would NOT have saved her from cancer, so what is the best for her ? prayers for strength to cope and prayers of thanksgiving for all the gifts of children she has given life to, and been given to..... i know a little about this kind of pain...my husband has battled acute leukemia for the past 10 years and it's not over yet. but we have been blessed with him and the children they said we'd never have (all whom were breastfed). I often wonder if he would have gotten leukemia if my mother-in-law had Brfed her sons ????? But does it really matter now ??????? The only regret we should have is wasting so much precious time having regrets.....