Explain how decreased levels of HLA class I on variant cancer cells can (A)enhance or (B)reduce tumor growth.

Question

Quizplus · Accepted Answer

The Answer is A. Enhancement of tumor growth occurs when cancer cells stop expressing HLA class I because these cells are no longer presenting tumor antigens to cytotoxic T cells. Variant cells are consequently able to escape immune detection.
B. Tumor cells that lack HLA class I are more susceptible to attack by NK cells. The inhibitory receptor on NK cells fails to engage normally, and this causes tumor cell killing after the activation and release of cytotoxic molecules by the NK cell.

Explain How Decreased Levels of HLA Class I on Variant