Are there malignant symptoms that can manifest after assisted reproduction?

No, or rarely: There have been many studies looking at a link between fertility therapies and cancer. To date, there is no link. However, there is a very rare condition called an ovarian tumor of low malignant potential that may occur at a slightly higher percentage after fertility therapy. Conversely, infertile women get more cancers than fertile women, regardless if they have had therapy, or not.