Final answer:
The process when cancer cells invade neighboring tissues is known as invasion, and it is a characteristic of malignant tumors. Cancer can also spread through lymphatic channels or via the blood, leading to metastasis which can create new tumors in other parts of the body.
Step-by-step explanation:
When cancer cells invade neighboring tissues, it is known as invasion. This process is one of the hallmarks of malignant tumors, which are cancerous growths able to grow beyond their original boundaries. Invasion refers to the intrusion on and destruction of adjacent tissues by the cancer cells.
Additionally, cancer can spread via the lymphatic system to regional lymph nodes or through the blood to distant sites, which is referred to as metastasis. Metastatic cancer cells can form new tumors in various tissues, worsening health outcomes significantly as they deprive normal organs of blood supply and nutrients.