Cancer is defined as?

• A. Benign tumor
• B. A type of autoimmune disease
• C. Infectious disease
• D. Any malignant growth or tumor caused by abnormal and uncontrolled cell division

Answer: (D)

Cancer is defined by uncontrolled, abnormal cell growth that forms malignant tumors capable of invading nearby tissues and spreading to distant sites. This distinguishes cancer from benign tumors, which are not invasive or metastatic. It also sets apart cancer from autoimmune diseases, where the immune system attacks the body's own tissues, and from infectious diseases, which are caused by pathogens. The underlying idea is that cancer arises when genetic mutations disrupt cell-cycle control, apoptosis, and cell adhesion, allowing cells to proliferate without normal checks and to invade or metastasize. That combination—malignant growth plus abnormal, uncontrolled division—is what defines cancer.