Metastasis (noun)

1. The spread of a disease, especially cancer, to another part of the body.
2. The transfer of a disease from one organ or part to another without a known cause.

Origin:

From the greek μετάσταση (metastasis) meaning "a change".

Examples:

1. The metastasis of the cancer to her lungs was what ultimately led to her death.
2. The tumor was found to be in an advanced stage of metastasis.
3. The patient was diagnosed with metastasis in his liver.
4. Surgeons removed the tumor and surrounding tissue to prevent metastasis.
5. The patient's metastasis to the bones made treatment difficult.