Tumor-associated antigens are?

• A. Unique to cancer cells
• B. Unique to benign cells
• C. Unique to benign and cancer cells
• D. Not present

Answer: (C)

Tumor-associated antigens are antigens found on tumor cells that are also present on some normal cells, often in normal tissues at lower levels or in a different context (for example, as differentiation antigens or overexpressed normal proteins). Because they are shared with normal cells, they are not exclusive to cancer. This means they can appear on both benign and malignant cells, which is why the term “tumor-associated” emphasizes their presence in tumors but not their uniqueness to cancer. This is in contrast to tumor-specific antigens, which are unique to cancer cells and not found on normal cells.