The phrase "hitting the wall" is used by marathon runners to describe the body's exhaustion as a race nears the 20th mile. Weakened by blood-sugar loss, dehydration and the physical demands of running 20 miles, it is not a feeling many nonrunners would like to endure.

But for Julia Khvasechko, who has experienced this feeling time and again as a marathon runner, it is nothing compared to the wall she hit when diagnosed with a brain tumor at age 24.

"When you hit a wall - for me that is around mile 19 - it's easy to give up, but one cannot give up, one has to keep going," she said. "That is what I learned from overcoming a chronic condition. The initial reaction to the diagnosis was that my life was over. I was so very young - I lost my innocence, my youth and my carefree lifestyle. And it was not an easy road after the diagnosis, either."

After an incorrect diagnosis of epilepsy in 1994, Khvasechko was diagnosed with a brain tumor in 1998.

Now, she has attained the health status of someone who never had a brain tumor because after seven years survivors are considered no more likely to develop another tumor than someone who has never had one.

Khvasechko, 31, has become a runner to raise funding and awareness for brain tumor research, and in April, she will marry her running partner, Chris Pierson of Sioux Falls, and move here, leaving her job as a commodities trader in New York City,

For Pierson, who is operations manager at P&M Steel in Sioux Falls and an avid outdoorsman and adventure racer, training with Khvasechko and running to support people affected by brain tumors has been rewarding on many levels.

"I've always wanted to be more into volunteering and giving back where I can, and having met Julia, it has more meaning because she's a survivor," said Pierson, 41. "It's like I'm saying 'thank you' to someone or something for her being a survivor."

The couple met online last year, and after months of averaging 12 to 20 miles a day running during their shared training routines - she in New York, he in South Dakota - they are looking forward to a goal of racing in every state to raise money and awareness for brain tumors.

The couple recently worked with Jennifer Neale, a survivor and National Brain Tumor Foundation volunteer, as a racing team. On Sunday, the couple will race in the Los Angeles Marathon through the foundation's Racing Ahead program to promote awareness and raise money for research.

Founded in 1981, the National Brain Tumor Foundation is a nonprofit organization devoted to educating patients, family and friends about research for this uncommon cancer.

"Unlike other, more common cancers, we know less about how to prevent (brain tumors) and find them early," said Heather Denkert, state vice president of the American Cancer Society. "Awareness efforts around cancer typically focus on what action people can take to minimize their risk, such as quitting smoking or getting a mammogram. There is no equivalent for detecting brain cancer in someone at average risk who doesn't have symptoms."

The American Cancer Society estimates brain cancers make up only about 1 percent of all cancers, but nearly 190,000 people are diagnosed with a brain tumor each year, according to the National Brain Tumor Foundation.

With more than 120 types of brain tumors, effective diagnosis and treatment can be tricky.

Most brain tumors are called gliomas, according to Sioux Valley Oncology's Dr. Michael Keppen, and the correct diagnosis and prediction of the tumor's severity can be difficult.

"Glioma is a cancer in the supporting structure of the brain - it's not the brain cells, it's the surrounding tissues that change," he said. "Depending on the location, there may be symptoms right away, but they may also take time to develop."

Khvasechko, who had two tumors, dealt with an especially rare form of cancer, an oliodendroglioma, which constitutes about 5 percent of all gliomas.

Patients frequently undergo more than one surgery to treat this type of cancer, and Khvasechko was given only a 30 percent chance of survival.

Because of its very nature, a brain tumor has the potential to affect every part of the body, sometimes inducing seizures and loss of mobility and mental function. And because the length of time from diagnosis to death can be quick, the relatively few number of brain cancer survivors might have something to do with the disease's unknowns - something Khvasechko hopes to change as she and Pierson race for brain tumor recognition.

"At the very least, running a marathon as a survivor spreads hope to those newly diagnosed. If I can spread some hope somewhere, then I'm doing my job," she said. "I'm making a difference, and I'm doing something that matters. For nearly a year, I was unable to walk to the end of the block by myself, and now I run marathons."

It is this spirit of giving back that puts Khvasechko on par with celebrities such as Lance Armstrong who tell their stories to promote awareness.

"It always helps to have a famous celebrity get a cancer (to promote awareness)," Keppen said. "It's a sad reflection of our society, but it seems like the cancer of the week depends on who's been diagnosed with it."

Khvasechko might not have national media attention or the resources of Armstrong, but she is doing what she can. She exceeded her goal to raise $5,500 from sponsors on her Firstgiving Web page [www.firstgiving.com/julesjourney] for the Los Angeles marathon, and she will have a new page set up for the San Francisco marathon after that.

While the majority of funding for cancer research comes from the federal government and the American Cancer Society, it is survivors such as Khvasechko who personify this disease for the public and make a personal difference.

"I applaud the efforts of Julia Khvasechko to increase awareness of this disease," Denkert said. "Much of the awareness that has been generated around other types of cancer is due to survivors willing to put a face on the disease and educate others about its impact. This kind of awareness can help motivate others to contribute to organizations that support research that will save lives."