In order for a cancer to metastasize, cells must gain migratory abilities and invade other tissues.

On microscopic examination, the cancerous cells invade and replace the surrounding normal tissues.

If the leukemic cells invade the central nervous system, then neurological symptoms (notably headaches) can occur.

If left untreated, the damaged cells can invade the next layer of skin and form a cancerous tumor.

The cells invade and we fight back.

These cells can invade nearby tissues and form a mass, called a malignant tumor.

When the first immune cells invade the joint, they send out chemical messages through the bloodstream to call in reinforcements.

The cells may multiply recklessly and invade areas where they don't belong.

We know now that deviant cells, some growing, and some benign, had invaded her nervous system, sometimes putting pressure on an organ or nerve.

These cells may invade the whole endometrium and the proximal third of the myometrium.