The future of cancer research

Regional science fair winner explored an aspect of radiation treatment of cells

March 26, 2006|By KAREN NITKIN | KAREN NITKIN,SPECIAL TO THE SUN

Danna Thomas, the grand-prize winner of the Anne Arundel County Regional Science Fair, is fascinated by radiation.

This is a phenomenon, she points out, that can cure cancer, but also cause it.

Danna, 16, a junior at Broadneck High School, hopes to be an oncologist, though she's not sure yet if she wants to focus on research or treatment. Meanwhile, she's been busy studying the effects of radiation on cells.

Last year, that interest earned her second prize in the county's regional science fair. And this year, she took the grand prize.

For this year's project, Danna focused on a new area of study, something called the "bystander effect." In the past, scientists thought that cells were affected by radiation only if it were directly in the nucleus, she explained.

But evidence indicates that cells communicate their radiation to each other, so that even cells that were not irradiated can show the effect.

The implications for cancer prevention and treatment are tremendous. If a doctor is using radiation to shrink a tumor, is that radiation also increasing the chances of getting cancer in the future?

Danna's winning research indicated that the bystander effect does exist for cells that are treated with ionizing radiation, the kind that is used in radiation treatment. So radiation on a person's left leg, for example, might affect other parts of that person's body.

Or, as she wrote in her abstract: "The results of my study support the hypothesis for the existence of radiation-induced instability and the existence of bystander effects."

"She's a wonderful student," said her Advanced Placement chemistry teacher, Jody Jallepalli. "This was really something she did on her own, in her own time."

Back in her sophomore year, Danna studied the impact of non-ionizing radiation on fruit flies, taking flies that she purchased from a mail-order company and placing them in the path of radiation.

Working with Sujata Ives, a science teacher at Severna Park High School, she was able to extract chromosomes from the larva and determine that the chromosomes had become unstable, a condition that can lead to cancer.

About the same time, she learned that some police officers were developing testicular cancer, perhaps because they were holding radar guns in their laps. Danna invented a lead shield for the radar guns. She has a patent pending, she said, but she hasn't worked to market the product.

Meanwhile, as second-place winner in the regional science fair, she was able to take her fruit fly project to the International Science and Engineering Fair. (She'll be attending again this year.) While she was there, she realized "that in order to take my project to the next level, I needed to find a mentor," she said.

Over the summer, she sent out packets of information to various professionals, hoping that someone would help her. "I basically harassed a bunch of professors all over the place," she said.

She heard back from Dr. William Morgan, director of the Radiation Oncology Research Laboratory at the University of Maryland, Baltimore. "We thought it was pretty cool that a high school student was doing some of this stuff," Morgan said.

Morgan met with Danna and set her up with a mentor, Janet Baulch. "She was really the one that taught me the methods and really helped me out along the way," Danna said.

Danna went to the lab after school, she said, balancing her science project with other responsibilities, including her role in the school marching band. "For the past few months, I was up there every single day after school," she said.

The laboratory had recently acquired a unique piece of technology called an electron microbeam, which is capable of irradiating a single cell within a population, without damaging adjacent cells.

Danna used the microbeam to test Chinese Hamster Ovarian Cell Human Chromosome 4, a hamster cell with a human chromosome inserted. She created three groups: a cell population that was not irradiated at all, one in which 10 percent of the cells were irradiated, and one in which 100 percent were irradiated.

She was hoping to find an increase in unstable chromosomes in the 10 percent group, indicating the bystander effect. She did find some increase, but not enough to be statistically significant, she said.

But she did notice something else: a cell reaction known as a "kick-out," in which clusters of cells literally kick away from the rest of the group. "Something's wrong if they totally kick out this chromosome 4," she said. The 10 percent group had 9.5 percent kick-outs, compared to 9.71 in the 100 percent irradiated group.

"The 10 percent irradiated group would be expected to display 10 percent of the number of kick-outs observed in the 100 percent group if no bystander effect had occurred," she wrote. "However, the similar increase of kick-outs in the 10 percent irradiation group compared to the number of kick-outs in the full irradiation group supports my hypothesis of bystander-induced genomic instability."

This finding was important. "It's a really good foundation for further study," she said.

So what's next? Maybe she will do similar experiments with different cell lines, or examine the results of irradiation in different time frames. Danna would also like to find out exactly how these cells communicate with each other.

"It's so exciting to be in the lab," she said.

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