Researcher Investigates Mesothelioma Cancer Cells

Research Matters, Breathe Easy news magazine, Fall 2002/Winter 2003

MESOTHELIOMA is an incurable form of cancer that strikes the lung lining. It’s so deadly because the tumors don’t respond to current cancer treatments and Claire Vivo, Ph.D., wants to know why.

"It is important to understand the mechanism of death in malignant cells," says Dr. Vivo, who is working on a research project funded by the American Lung Association of California to find out how these cells work.

This type of cancer attacks the mesothelial cells, which form a protective lining around the lungs, heart and abdominal organs. The most common type of mesothelioma is found in the thin membrane between the lung and the chest cavity called the pleura.

All cells are programmed to die eventually. Cancerous tumors may be the result of cells that have lost their ability to die. Chemotherapy, radiation and other cancer treatments are often successful at triggering cell death, but not in mesothelial cells.

Researchers have found that the cells will die when a certain molecule that induces death is applied in conjunction with chemotherapy drugs, but they don’t know why. Dr. Vivo is trying to understand the mechanism so that someday better treatments can be developed, and possibly even a cure.

Asbestos Fibers Cause Lung Disease

Mesothelioma strikes about 3,000 people a year and is mainly caused by asbestos, a fibrous material mined from serpentine rock that was used in building materials, car brakes, and other products up until the mid-1970s. Although asbestos is no longer widely used, old buildings and products containing asbestos are still in use.

Another source of asbestos is naturally occurring asbestos, which covers about 1.2 percent of California’s landmass. All types of naturally occurring asbestos are potentially dangerous when they become airborne due to construction or activity. However, one type of asbestos called tremolite is more likely to cause mesothelioma.

Tremolite is present in the Sierra foothills where it is being disturbed by development, which is causing concern among many residents there. Last year, the American Lung Association of California and its medical section, the California Thoracic Society, urged the California Air Resources Board to adopt stringent air monitoring standards at construction sites and mining operations where naturally occurring asbestos is present.

Cases are Expected to Rise

Experts predict mesothelioma will strike even more people in the years to come. The Mesothelioma Legal Center estimates that by 2030, there could be a total of 300,000 mesothelioma cases because it can take anywhere from 15 to 50 years to develop after exposure to asbestos. That means all the people who may have inhaled asbestos fibers while it was still in use could still develop mesothelioma, not to mention people who are currently being exposed when old building materials are disrupted or naturally occurring asbestos is disturbed.

"We have to find a way to kill these tumor cells," says Dr. Vivo.

Correction:
When this issue of Breathe Easy was originally published, it was incorrectly stated that "by 2030, there could be 300,000 new cases each year" of mesothelioma. We misquoted a report by the Mesothelioma Legal Center, which actually stated there would be a total of 300,000 mesothelioma cases by 2030, with 3,000 new cases each year. But experts say even that figure is high. The most reliable estimates indicate there will be approximately 1,430 new male cases and 500 new female cases in the year 2030. The estimate for males reflects the downward trend in mesothelioma, which peaked at about 2,250 new cases in 2002. The number of new cases for females has been approximately constant at 500 per year.