: To occur again. Recurrence is the return of cancer, at the same site as the original (primary) tumor or in another location, after the tumor had disappeared.

(SEE-bum): An oily substance produced by certain glands in the skin.

: Skin that is moved from one part of the body to another.

: Sun protection factor, scale for rating the level of sunburn protection in sunscreen products. The higher the SPF, the more sunburn protection it provides. Sunscreens with an SPF value of 2 through 11 provide minimal protection against sunburns. Sunscreens with an SPF of 12 through 29 provide moderate protection, which is adequate for most people. Those with an SPF of 30 or higher provide high protection against sunburn and are sometimes recommended for people who are highly sensitive to the sun.

(SKWAY-mus. . .kar-sin-O-ma): Cancer that begins in squamous cells, which are thin, flat cells resembling fish scales. Squamous cells are found in the tissue that forms the surface of the skin, the lining of the hollow organs of the body, and the passages of the respiratory and digestive tracts. Also called epidermoid carcinoma.

(SKWAY-mus): Flat cells that look like fish scales under a microscope. These cells cover internal and external surfaces of the body.