National Cancer Institute - Dictionary of Cancer Terms

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Q10

A substance found in most tissues in the body, and in many foods. It can also be made in the laboratory. It is used by the body to produce energy for cells, and as an antioxidant. It is being studied in the treatment of cancer and in the relief of side effects caused by some cancer treatments. Also called coenzyme Q10, CoQ10, vitamin Q10, and ubiquinone.

QS21

A plant extract that may improve the ability of the immune system to respond to disease. It is being studied in combination with vaccine therapy.

quadrantectomy

Surgical removal of the region of the breast (approximately one quarter) containing cancer.

quality of life

The overall enjoyment of life. Many clinical trials assess the effects of cancer and its treatment on the quality of life. These studies measure aspects of an individual's sense of well-being and ability to carry out various tasks.