HARVARD -- Charlotte O'Shea was a happy and loving little girl. She enjoyed taking ballet lessons with her dance teacher, Miss Kate. She loved doing art with her brother, James, and wanted to grow up to be a vet with him someday. Charlotte had a miniature dachshund, Maisey, who would lie in bed with her when she was sick.

Charlotte and her twin brother, Will, spent most of their early childhood at the Jimmy Fund Clinic, where they knew all the doctors and nurses and kept all their stickers and prizes.

Charlotte had a rare childhood cancer called AT/RT that affects the brain and spinal cord. She battled this brain cancer for almost five years of her young life. Charlotte died in December of 2010 at age 6.

According to Charlotte's mom, Janet O'Shea, there was barely any treatment available for this cancer when she was diagnosed. An atypical teratoid rhabdoid tumor, often called AT/RT, is a very rare and fast-growing tumor of the central nervous system that usually occurs in children under 3 years old. Only 30 cases per year are diagnosed, according to Dr. Charles Roberts of Dana Farber Cancer Institute, one of the world's leading experts on AT/RT.

O'Shea remarked that although Charlotte's brain cancer is rare and there was previously very little research on this disease, cancer is actually the second leading cause of death in children 5 to 14 years old (accidents/unintentional injuries are the leading cause of death in children), according to the Centers for Disease Control and Prevention.

Charlotte was in treatment for almost five years with another Bay State girl, Avalanna Routh of Merrimac, who brought this rare disease to the international forefront with her pretend wedding to Justin Bieber on Valentines' Day last year. Avalanna also sadly passed away at age 6 in September of 2012. The O'Shea and Routh families became close during this time, and wanted to do more to help battle childhood brain cancer. They started the Cure AT/RT Now fund because there was no money given to this disease for research and there were three renowned researchers at the Jimmy Fund Clinic -- Dr. Charlie Roberts, Dr. Susan Chi and Dr. Mark Kieran.

Since 2008 this fund has raised more than $1 million with the help of the Pan Mass Challenge and the Jimmy Fund Walk. Charlotte was a PMC Pedal Partner in 2010. The Jimmy Fund selects children in treatment and matches them up with teams. Charlotte was matched as the Pedal Partner for Team Nine, the Red Sox Team for which Stacey Lucchino was captain. That was the O'Shea's first experience with the PMC. Charlotte got to throw the first pitch when she was the pedal partner.

Janet O'Shea has been riding in the Pan Mass Challenge since 2011 in her daughter's memory. Charlotte's big brother, James O'Shea, is also riding in her memory this year to help find and fund a cure. James is a freshman at the Bromfield School in Harvard where his dad, Jim O'Shea, is principal. Janet and son James both ride for Team Lick Cancer, which is out of Janet's hometown, Acton. The captain of Team Lick is Dave Christmas of Christmas Motors. Janet asked Team Lick in 2009 to restrict fundraising to lick AT/RT, and Christmas says that more than half of the funds are committed to AT/RT.

"Ours is the only team for AT/RT research," said Christmas. "Over the past three years, we have given $900,000 for doctors to do research on AT/RT. We are devoted to this research." Christmas remembers Charlotte as a "positive and really wonderful little girl."

One of the great things about the PMC, according to Janet O'Shea, is that 100 percent of the money donated goes directly toward research.

"The PMC is a great way to donate money to research," said Janet O'Shea. "It's the parents that raise the money for pediatric cancer research. They realize there is no research, no new treatments for their child."

Researchers at Dana Farber report that Team Lick is making a major difference in their fight to find a cure for AT/RT, and also a variety of cancers they recently discovered have the same genetic lesion that causes growth of AT/RT. These include cancers of the lung, stomach, pancreas, liver, ovary, kidney, colon, bladder, skin and brain. As a result, the researchers at Dana Farber will begin a trial of a first generation drug within a year, and will have their first clinical trial this month.

"The bottom line is that ongoing support from Team Lick has enabled our achievements and is central to our ongoing work," said Charles W. M. Roberts, M.D., Ph.D., Dana Farber Cancer Institute. "We are hopeful that this will lead to cures not only for children, but also for adults suffering from related cancers."

The Pan Mass Challenge is in August.

Charlotte O'Shea was a courageous girl throughout her life. She wanted to be on the swim team like her older sister Katherine, so despite traveling to NYC for a clinical trial, she would go to swim team practice at the Westford Swim and Tennis Club and compete at every meet. Charlotte frequently announced that she may have broken a world record after she raced. Charlotte loved the Red Sox and took every opportunity to meet Wally the Green Monster and many of the players. She was even spotted out on the field yelling "play ball!"