Despite a cloudy, overcast day, more than 300 people visited the University’s dermatology department Monday for skin cancer screenings.

Exposure to the sun’s harmful ultraviolet rays happens year-round, even in cold weather, said Peter Lee, a professor of dermatology.

The department offered free screenings for the seventh year as part of Melanoma Monday, a nationwide event that seeks to raise awareness of skin cancer and promote regular skin examinations.

The event offered free exams to people who noticed something abnormal on their skin but did not want to wait three or four weeks to see a dermatologist, said Lee, the University’s Dermatologic Surgery and Laser Center director.

“The goal is to identify any atypical lesions,” he said.

Lee said approximately one-fifth of the people who came to the screenings would require further treatment.

Doctors at the event saw lesions that could be one of the three types of skin cancer, said Bertha Lin, a professor of dermatology.

Malignant melanoma, which is the deadliest form of skin cancer, can develop near a pre-existing mole with features similar to a mole, Lin said.

Therefore, moles that are asymmetrical or have notched, irregular borders are cause for concern, she said. Also, moles that have multiple colors, change in size, or are more than 6 millimeters in diameter should be examined, she said.

Lee said a common misconception about moles is that they must be raised to be of concern. A flat mole can be dangerous as well, he said.

To avoid skin cancer, Lee suggests limiting sun exposure.

“Sun exposure is the No. 1 risk factor, so not getting sunburned is key,” he said.

Spending too much time in the sun can also lead to wrinkles and unattractive brown spots, he said.

“Protecting yourself from excess (sun) will help in the long run, cosmetically as well,” Lee said.

People should not be expected to stay out of the sun but to wear proper clothing and sunscreen when they are outside, Lee said.

When someone ages, his or her chance of developing skin cancer increases.

“Every time you get a sunburn, your cells take a hit from UV rays and you get DNA damage,” Lee said.

As a person gets older, he or she loses the ability to repair damaged DNA.

In addition to the sun, people should avoid tanning booths, because they emit a “heavy dose of (ultraviolet) rays,” Lee said.

Although the Food and Drug Administration labeled ultraviolet rays a carcinogen, Minnesota state laws regarding tanning-booth usage are “loose,” Lee said.

Lin said diagnoses of the three types of skin cancer are increasing because of outdoor recreational activities, sunbathing and the increased popularity of tanning beds.

Megan Knisely, a biomedical engineering junior, said she sunbathes outside whenever the weather is nice. She also visits tanning booths a few times each week for approximately one month before going on warm-weather vacations, she said.

Knisely, who did not attend the screenings, said she knows about the dangers of ultraviolet radiation exposure but isn’t concerned about developing skin cancer now.

“(Tanning) just makes me feel good,” she said. “The sunshine, the warmth; it’s one of my favorite things.”