Even while the immune system can stop or slow cancer growth, cancer cells have developed ways to avoid immune system destruction. This occurs in most cases because cancer cells:
They’ve undergone genetic modifications that make them less visible to the immune system.
Have proteins on their surface that cause immune cells to shut down.
Change the normal cells in the tumor’s environment so that they obstruct the immune system’s response to the cancer cells.
Immunotherapy works by preventing cancer cells from avoiding the immune system and stimulating the immune system to attack cancer cells.