Melanoma is one of the most common types of skin cancers in the U.S. Each year over 68,000 Americans are diagnosed with melanoma. This type of skin cancer usually begins as a tumor in the cells that make the pigment melanin, called "melanocytes." Melanin is responsible for skin color and although melanoma predominantly occurs in the skin, it can also attack the eyes or intestines.

In American children from birth to 19 years old, melanoma has increased 2 percent per year from 1973 to 2009. According to the Skin Cancer Foundation, melanoma accounts for up to 3 percent of all pediatric cancers. Melanoma is not often common in kids, but a new study suggests that it's on the rise. The study looked at 1,317 children diagnosed with melanoma; 1,230 of them where white. Researchers analyzed the melanoma cases of the white children, since their cases were the majority, compared to other races and ethnicities.

"It is rare, but children do get melanoma. When in doubt, get it checked out. The good news is that we know how to prevent melanoma, and when we catch it early, we have really good cure rates," Dr. Michele Green, a dermatologist at Lenox Hill Hospital in New York City, said.

The results of the study showed that the largest increase in cases was among teenage girls. Researchers theorize that the increase may be due to increased exposure to ultraviolet radiation. The exposure comes from either natural sunlight or tanning booths. The researchers did not have the participants' tanning habits to further investigate.

"Sunscreen and/or sun protection are so important for children. Don't ignore changing moles, even in children, because melanoma can occur in kids," said Dr. Ana Duarte, director of pediatric dermatology at Miami Children's Hospital. Results of the study were published in the journal Pediatrics.