Who has info on the relation between in vitro fertilization treatment medications and breast cancer ?

Depends.: Repeated use of ivf medications without success (i.e. Without pregnancy) can stimulate tumorigenesis on the breast tissue, especially in genetically predisposed women. On the other hand, if ivf results in the desired outcome (pregnancy), the risk of breast cancer will decrease because of the protective effect of placental progesterone.

A good question: To my knowledge there is ongoing research to figure out the potential impact of fertility treatment-hormonal-on the development of breast cancer. There is some indication that "many attempts" at in vitro fertilization many somewhat increase a woman's risk of breast cancer. Because, we do not have a precise way of predicting a woman's risk, it is a question to ask your fertility specialist. Luck.