Chemotherapy Biotherapy Certification ONS Practice Testq

Which of the following cells does not recognize cancer as a foreign invader?

1. Natural killer cells

2. Macrophages

3. Monocytes

4. B cells

The correct answer is: Natural killer cells

Natural killer cells are specifically designed to recognize and destroy cancerous cells as well as cells infected by viruses. They are a crucial part of the innate immune response and play an essential role in identifying abnormal cells that may not present strictly foreign antigens but are deviant from normal cell behavior. In contrast, macrophages, monocytes, and B cells all have distinct functions in the immune response. Macrophages are phagocytic cells that can engulf and digest cellular debris and pathogens, but they can also recognize cancer cells. Monocytes circulate in the bloodstream and can differentiate into macrophages; they share similar capabilities in recognizing and acting against cancer cells. B cells produce antibodies that can target cancer-specific antigens, further contributing to the immune response against tumors. Thus, natural killer cells accurately stand out as the cells that are specifically effective in identifying and destroying cancer cells, categorizing the other listed options as cells that are indeed involved in recognizing cancer cells.