Skin cancers -- including melanoma, basal cell carcinoma, and squamous cell carcinoma -- often start as changes to your skin. Most often it develops on skin exposed to the sun, but it can also occur on areas of your skin not ordinarily exposed to sunlight. These skin changes can be new growths or precancerous lesions. An estimated 40 to 50 percent of fair-skinned people who live to be 65 will develop at least one skin cancer. Here are some of the signs to look for: A solar keratosis consists of small, scaly patches that commonly occur on the head, neck, or hands, and are often caused by too much sun. They can be an early warning sign of skin cancer, but it’s hard to tell whether a particular patch will continue to change over time and become cancerous. Fair-skinned, blond, or red-haired people with blue or green eyes are most at risk. Related to solar keratosis, a “farmer's lip” is a precancerous condition that usually appears on the lower lips. Scaly patches or persistent roughness of the lips may be present. Less common symptoms include swelling of the lip, loss of the sharp border between the lip and skin, and prominent lip lines. A funnel-shaped growth that extends from a red base on the skin often referred to as “cutaneous horns.” It is composed of the same protein found in nails. The size and shape of the growth can vary considerably, but most are a few millimeters in length. It usually occurs in fair-skinned elderly adults with a history of significant sun exposure. Moles are benign growths of melanocytes, cells that give skin its color, and typically are not pre-cancerous. Although very few moles become cancer, abnormal or atypical moles can develop into melanoma over time. So-called “atypical moles” can become cancer. They are usually found in sun-exposed or sun-protected areas of the body. Atypical moles may be larger and more irregular in shape than normal moles, with notched or fading borders. They may be flat or raised or the surface smooth or rough. They are typically of mixed color, including pink, red, tan, and brown. Each year there are more new cases of skin cancer than the combined incidence of cancers of the breast, prostate, lung and colon. Early detection of skin cancer gives you the greatest chance for successful skin cancer treatment.