<span>Metastasis, or metastatic disease,
happens when cancer spreads from one organ or part to another part that is not
directly connected with it. Scientist used to believe that metastasizing only
happens to malignant tumor cells and infections. However, new research has caused
this to be reexamined because it was found out that even with the absence of
primary tumors, metastatic cancers were discovered adding to the idea that
metastasis are not only caused by malignant tumors that leave primary ones.</span>
