If a Tumor Metastasizes,this Means That It Has Moved to Another

If a tumor metastasizes,this means that it has moved to another part of the body.Doctors often look in lymph nodes near a tumor for signs of metastasis.Why might cancer cells be found in lymph nodes?

A) because the tumor started in the lymph node
B) because the lymphatic system collects fluids and cells from tissues
C) because white blood cells are formed in lymph nodes in response to the tumor
D) because the tumor is recognized as a foreign antigen and is being attacked
E) because the tumor cells may have moved from the blood into the lymph with the plasma