Cells that lack proper control of the cell cycle and can invade other tissues are referred to as

• A. Cancer cells
• B. Normal cells
• C. Stem cells
• D. Quiescent cells

Answer: (A)

Uncontrolled growth with the ability to invade other tissues describes cancer cells. These cells have mutations that disrupt normal cell-cycle controls, so they keep dividing despite signals to stop, and they often lose the adhesion and tissue boundaries that keep cells in place. They also acquire changes that let them break through surrounding structures and spread to new locations (metastasis). Normal cells are tightly regulated and respect tissue boundaries; stem cells can divide but are controlled and usually remain within their developmental context; quiescent cells are sitting in a non-dividing, resting state. So the description aligns with cancer cells, which combine unchecked proliferation with invasive behavior.