High Quality Content by WIKIPEDIA articles! Metastasis, or metastatic disease (sometimes abbreviated mets), is the spread of a disease from one organ or part to another non-adjacent organ or part. It was previously thought that only malignant tumor cells and infections have the capacity to metastasize; however, this is being reconsidered due to new research. The word metastasis means "displacement" in Greek, from μετά, meta, "next," and στάσις, stasis, "placement." The plural is metastases.