Carcinoma is a type of cancer that arises from which tissue?

• A. Malignancy arising from connective tissue that supports organs
• B. Malignancy arising from nervous tissue
• C. Malignancy arising from muscle tissue
• D. Malignancy arising from epithelial cells that line organs and body surfaces

Answer: (D)

Carcinoma is a cancer that originates from epithelial tissue—the cells that line surfaces and cavities of organs and glands, such as skin, the lining of the digestive tract, and respiratory tracts. These epithelial cells form the barriers and secretory surfaces of the body, and when they undergo malignant transformation, they produce carcinomas. Other cancers come from different tissues: connective tissue gives sarcomas, nervous tissue gives tumors of nerve cells, and muscle tissue gives muscle cancers. So carcinomas are defined by their epithelial origin, with examples like squamous cell carcinoma from squamous epithelium and adenocarcinoma from glandular epithelium.