HARVEY Pass, the chief of thoracic surgery at the National Cancer Institute, in Bethesda, Maryland, was sitting in his laboratory one spring afternoon in 1993 when Michele Carbone, a wiry young Italian pathologist who was working as a researcher at the NCI, strode in with an unusual request. Pass had never before met Carbone, and had talked to him for the first time, on the telephone, only a few hours before. Now Carbone was asking Pass for his help in proving a controversial theory he had developed about the origins of mesothelioma, a deadly cancer that afflicts the mesothelial cells in the lining of the chest and the lung. Mesothelioma was virtually unheard of prior to 1950, but the incidence of the disease has risen steadily since then. Though it is considered rare -- accounting for the deaths of about 3,000 Americans a year, or about one half of one percent of all domestic cancer deaths -- the disease is particularly pernicious. Most patients die within eighteen months of diagnosis.
Pass, one of the world's leading mesothelioma surgeons, knew, like other scientists, that the disease was caused by asbestos exposure. But Carbone had a hunch he wanted to explore. He told Pass that he wondered if the cancer might also be caused by a virus -- a monkey virus, known as simian virus 40, or SV40, that had widely contaminated early doses of the polio vaccine, but that had long been presumed to be harmless to people.
Pass listened as Carbone described for him the history of the early polio vaccine. A breakthrough in the war against polio had come in the early 1950s, when Jonas Salk took advantage of a new discovery: monkey kidneys could be used to culture the abundant quantities of polio virus necessary to mass-produce a vaccine. But there were problems with the monkey kidneys. In 1960 Bernice Eddy, a government researcher, discovered that when she injected hamsters with the kidney mixture on which the vaccine was cultured, they developed tumors. Eddy's superiors tried to keep the discovery quiet, but Eddy presented her data at a cancer conference in New York. She was eventually demoted, and lost her laboratory. The cancer-causing virus was soon isolated by other scientists and dubbed SV40, because it was the fortieth simian virus discovered. Alarm spread through the scientific community as researchers realized that nearly every dose of the vaccine had been contaminated. In 1961 federal health officials ordered vaccine manufacturers to screen for the virus and eliminate it from the vaccine. Worried about creating a panic, they kept the discovery of SV40 under wraps and never recalled existing stocks. For two more years millions of additional people were needlessly exposed -- bringing the total to 98 million Americans from 1955 to 1963. But after a flurry of quick studies, health officials decided that the virus, thankfully, did not cause cancer in human beings.