Raoul Aponte relaxes between classes at the Johns Hopkins University.

Rays: Raoul Aponte, a freshman from Cleveland, relaxes between classes at the Johns Hopkins University. Experts recommend wearing sunscreen and limiting time in the sun. (Sun photo by John Makely / May 2, 2001)

Jennifer Martin was 28 years old and three months pregnant when a doctor diagnosed her malignant melanoma, the most deadly type of skin cancer.

Fifty years ago, the disease rarely struck people in their 20s. Now, it is one of the most common types of cancer in young women. In the past 20 years, the incidence of melanoma more than tripled in Caucasians. Nationwide, 51,400 new cases of melanoma are expected this year - a 9 percent increase over last year.

Doctors have known for years that overexposure to the sun is a leading cause of melanoma and other skin cancers and have tried to spread the message that people should wear hats, apply sunscreen and stay out of the sun. Yet the public has been slow to react.

At the Johns Hopkins University this time of year, students flock to the grassy hill in front of the library affectionately nicknamed "the beach." They throw Frisbees, do homework and work on laptops. Men take off their shirts; women wear sports bras or bathing suits.

Nobody seems concerned about skin cancer.

"I don't come out here to get tan," said Genevieve Gallagher, an 18-year-old freshman from outside Pittsburgh who on Monday was studying organic chemistry in her bikini. "It's usually, I'm out here studying anyway 'cause it's a beautiful day and why not get tan in the process?"

As the weather warms every year, doctors and nonprofit groups try to get the word out about the dangers of the sun. May is National Skin Cancer Detection and Prevention Month. Next Monday was declared Melanoma Monday by the American Academy of Dermatology, which will hold a screening for members of Congress today. Last year, Sen. John McCain of Arizona had melanomas removed from his face and arm.

Throughout summer, the Coalition for Skin Cancer Prevention in Maryland sends its mascot, SunGuard Man, to ballgames with tubes of sunscreen. During the school year, the organization sends representatives to teach youngsters about the sun's dangers.

Roberta M. Herbst, project coordinator for the coalition, said skin cancer rates are rising because of stronger ultraviolet radiation and large numbers of people who received two or more bad sunburns as children.

"Childhood sunburn is the leading risk factor," she said. "Two or more painful, blistering sunburns double a person's risk."

Yet it's no easy job persuading people to stay out of the sun on the first beautiful days of spring.

In Hampden on Monday, Mario Vecchio, 25, lay in Wyman Park between shifts at Papa John's, turning a deep red-brown under the cloudless blue sky. He said he worries about the hole in the ozone over Brazil, his native country, but not in Baltimore. He'll lie in the sun all summer, he said, and never apply sunscreen.

"We need the sun," he said. "The plants need the sun." Neither a jogger nor a woman reading in the sun nearby was wearing sunscreen, either.

At Hopkins, James Miller, a 22-year-old senior, put it this way: "If it's an option between going to classes and lying on the beach, people will lie on the beach."

Martin used to be a sun worshipper, too. Now 30, she was a freckle-faced girl with blond hair and blue eyes. She says her mother would drop her and her sisters off at the neighborhood pool in Owings Mills every day and pick them up five hours later. Martin spent summers at the beach and honeymooned in the Caribbean.

About seven years ago, Martin noticed that a mole on her back was growing and had a dermatologist remove it. Two pathologists said the mole looked suspicious, so the doctor removed more skin.

"Back then, melanoma never even popped into my head," she said.

Five years later, Martin's obstetrician found a lump in her breast. A biopsy showed that it was melanoma. Her mole had been malignant, and it had spread to her lymph nodes.

After many treatments, Martin's cancer is in remission, but it has changed her life forever - and not just because she now wears hats and protective clothing and visits her oncologist every three months for blood work and a chest X-ray to make sure the cancer hasn't come back.