True. Each year the number of new cases exceeds that of breast, colon, lung, and prostate cancer combined. About one in five Americans will develop skin cancer in their lifetime.

While a majority of cases are not life-threatening, they can be disfiguring. Left untreated, skin cancer can severely erode tissue and surrounding bone. Of the two most common forms, basal cell carcinoma (BCC) rarely spreads, but squamous cell carcinoma (SCC) occasionally does, often with fatal results.

Melanoma accounts for less than 5 percent of skin-cancer cases but causes more than 75 percent of deaths. Most disturbingly, melanoma continues to rise at a rate faster than that of any of the seven most common cancers.

False. Overall, men are at higher risk of melanoma because they tend to spend more time outdoors than women and are less diligent about using sunscreen. (Research suggests that they tend to pay less attention to their skin.)

Among Caucasians, over a lifetime, one in 58 women will develop melanoma; for men, the rate is 1 in 39. The trend is reversed among people under 40, possibly because young women spend more time tanning.

A 2009 study of men with a recent diagnosis of melanoma and their wives found that the women were better in terms of reading information about skin cancer, checking their moles, and using sunscreen.

True. The main reason seems to be that deadly cancers go undetected more often in people with darker skin until the condition reaches an advanced stage.

In a study of nearly 1,700 melanoma patients in Florida, half of the cancers of non-Hispanic black patients were in the late stage compared with only 16 percent of the cancers in non-Hispanic whites.

But the incidence of melanoma is lower in people with darker skin. And while Caucasians diagnosed with melanoma are significantly more likely to survive than they were 40 years ago, it's not the case for people of other races.

"People of color are less likely to get cancers on sun-exposed skin and more likely to develop them in places where they are harder to spot and diagnose correctly—under the fingernails or toenails, for example, or on the soles of the feet," says Adele Green, M.D., Ph.D., deputy director of the Queensland Institute of Medical Research in Brisbane, Australia."However, cancers in those locations in whites are also not likely to be diagnosed until they are advanced," she says.

True. "A lot" is roughly defined as about 50 or more. "Enough that someone standing across the room would notice them," Halpern says. Other factors that increase your skin-cancer risk include having any of the following:

• A parent, child, or sibling who had skin cancer.
• Red or blond hair, blue or green eyes, or a tendency to sunburn easily.
• Three or more blistering sunburns before age 20, or having worked outdoors three or more summers as a teenager.
• Lots of freckles, especially on your upper back.
• Actinic keratoses (persistent scaly patches of skin) or suspicious moles.

On average, one or two of those factors triples your risk of skin cancer; having three or more can increase your risk twentyfold.

False. You should examine your skin at least once yearly—the American Academy of Dermatology recommends that you "check your birthday suit on your birthday"—or more frequently if you are at higher risk. A thorough exam should cover all skin surfaces, including the scalp, genitalia, fingernails, toenails, palms, and soles of the feet. Use a full-length mirror and hand mirror to check the back of your body.

Most people discover abnormal growths themselves, although physicians seem to be better at spotting cancer at earlier stages. Because there's not much evidence to support widespread screening, there are no hard and fast guidelines. Our experts recommend that low-risk people have their primary-care doctor examine their skin as part of a regular checkup in addition to self-exams. People at higher risk might need to be screened more frequently, preferably by a dermatologist.

Sun exposure has been linked to all three of the major types of skin cancer. Some forms of squamous cell cancer are linked to risk factors such as radiation therapy, taking medication containing arsenic, burns, chronic nonhealing wounds, and diseases like lymphoma that suppress the immune system.

True. Even for melanomas, the five-year survival rate is 98 percent if caught before it reaches the lymph nodes. The survival rate drops to 15 percent if the cancer spreads to other organs.

Basal cell and squamous cell cancers are typically removed by freezing, burning, or cutting lesions along with a small surrounding area of normal skin. Lesions in more cosmetically significant spots can be removed using Moh's surgery, which preserves as much tissue as possible by excising and examining successive slivers until the site is cancer-free. Surgical removal almost always cures early melanoma as well.

Recent breakthroughs hold promise for treating advanced melanomas. In March 2011, the Food and Drug Administration approved ipilimumab (Yervoy), the first drug to clearly extend the lives of patients with late-stage melanoma. Although a recent study found that the average survival benefit for patients using the drug was only four months, some patients lived much longer.

Yervoy can cause serious adverse effects, including fatal autoimmune reactions, but researchers hope that combining it with other targeted therapies will extend life significantly.

True. Most people use it in a way that provides a sun protection factor of less than 10. To achieve the protection claimed on the label, adults should use about two tablespoons of lotion (or two-thirds of a standard shot glass) applied to the entire body.

Our experts recommend choosing a product with an SPF factor of at least 30, which applied scrupulously should allow you to stay in the sun without reddening 30 times longer than normal. The SPF factor refers to protection against the UVB form of radiation. Many products also claim to protect against UVA radiation, which has also been linked to skin cancer as well as premature aging. But there are no stringent requirements for U.S. manufacturers to inform consumers about the amount of UVA protection that a sunscreen provides. Recent tests by Consumer Reports found that sunscreens containing avobenzone provided a high level of protection.

False. It should actually take third place after wearing protective clothing (a long-sleeved shirt, pants or a long skirt, a broad-brimmed hat, and sunglasses) and staying out of the midday sun. When your shadow is shorter than you are, it's wise to seek shelter or shade.

False. Modest amounts of unprotected sun exposure during the summer months—about 2 to 8 minutes daily—should be enough for most people. But if you're rarely outside or scrupulous about using sunscreen, you should be sure to get the recommended 600 international units (IU) daily of vitamin D (800 IU for those older than 70) through supplements and fortified foods.

False. "We now have unequivocal evidence that tanning beds cause cancer," Halpern says. Recent evidence suggests that indoor tanning beds can quadruple your risk of developing melanoma.