NEW YORK — Dr. Renato Dulbecco, a virologist who shared a Nobel Prize in 1975 for his role in drawing a link between genetic mutations and cancer, died Sunday at his home in the La Jolla section of San Diego. He would have turned 98 tomorrow.
The National Research Council of Italy, where he had worked for many years, announced his death. He was a former president of the Salk Institute for Biological Research in San Diego.
Through a series of experiments that began in the late 1950s, Dr. Dulbecco showed that certain viruses could insert their own genes into infected cells and trigger uncontrolled cell growth, a hallmark of cancer.
The discovery provided the first solid evidence that cancer was caused by genetic mutations, a breakthrough that changed the way scientists thought about cancer and the effects of carcinogens, like some hair dyes and tobacco smoke.
“His research was the beacon that clearly showed that changes in the genome can lead to cancer,’’ said Inder M. Verma, a biologist and former colleague of Dr. Dulbecco’s at the Salk Institute.
Dr. Dulbecco shared the 1975 Nobel Prize for physiology or medicine with a former student, Howard M. Temin, and another researcher, David Baltimore. Temin, who died in 1994, and Baltimore studied viruses that carry their genetic information in the form of RNA.
Dr. Dulbecco looked at viruses that use DNA to store their genetic information. Dr. Dulbecco went on to study breast cancer, pioneering a technique for identifying cancer cells by their genetic signature: the unique proteins displayed on their surface. In 1986, he proposed cataloguing all human genes to gain deeper insights into cancer, providing the intellectual impetus for the Human Genome Project, which was completed in 2003.
Renato Dulbecco was born in Catanzaro, Italy, the son of a civil engineer. He loved tinkering as a child; he assembled a vacuum-tube radio so his mother could listen to opera, and built a working electronic seismograph. He graduated from high school at 16 and went on to the University of Turin, receiving his medical degree in 1936.
Inducted into the Italian Army as a medical officer in World War II, he was eventually ordered to the Russian front. He recalled that when the train taking him there stopped in Warsaw, he saw railway laborers wearing yellow stars. When he asked about them, he was told that the workers were Jews who would be killed when their work was done. He was horrified.
“That was my turning point,’’ he said in an oral history.
In Russia, he dislocated his shoulder and was sent home to recuperate. But instead of returning to the Army after his recovery, he hid in a village about 40 miles from Turin and joined the resistance. He remained in the village for the rest of the war, tending to injured partisans.
After Germany surrendered, he got involved with the Committee for National Liberation in Turin and joined the postwar city council. But he soon tired of politics and returned to the University of Turin to study physics and conduct biological research.
In 1947, a former University of Turin professor, Salvador Luria, recruited Dr. Dulbecco to Indiana University in Bloomington to study phages, viruses that infect bacteria.
Dr. Dulbecco joined the faculty of the California Institute of Technology in Pasadena in 1949, driving his family to the West Coast in “an old car,’’ as he recalled, hitched to a small trailer carrying their belongings. Shortly after his arrival, he shifted his studies to animal viruses; Cal Tech had received a $100,000 gift to finance the research and was looking for someone to do it. With Marguerite Vogt, who became a longtime collaborator, he developed a method of determining the amount of polio virus present in cell culture, a step that was essential to development of the Sabin polio vaccine.
Dr. Dulbecco soon turned his attention to the connection between viruses and cancer; he was intrigued by the work of his student, Temin, who wrote his thesis on the topic. Dr. Dulbecco started the research at Cal Tech and completed it at Salk, where he moved in 1962.
Working with Vogt and others, he experimented with viruses that were known to cause tumors in animals. In the 1950s, no viruses had been linked to human cancers. Since then, a handful of viruses have been shown to cause cancer in people, including the human papillomavirus, which is responsible for most cervical cancers.
Dr. Dulbecco believed his research had broad implications for cancer prevention. In his Nobel lecture, he urged governments to test the likelihood of new chemical substances causing mutations before allowing them on the market. He also called for severe restrictions on tobacco use. “While we spend our life asking questions about the nature of cancer and ways to prevent or cure it,’’ he said, “society merrily produces oncogenic substances and permeates the environment with them.’’
Dr. Dulbecco left Salk in 1972 to serve as a director of the Imperial Cancer Fund in London. He returned to Salk in 1977 and was its president from 1988 to 1992. He received the prestigious Albert Lasker Basic Medical Research Award in 1964. He became a US citizen in 1953.
He leaves his second wife, Maureen, and two daughters.