For contributions that laid the foundations for the chemotherapy of cancer.
Dr. Gross was the first to discover a leukemia-inducing virus in mice. He successfully employed this virus—the RNA-containing Gross leukemia virus (GLV)—in extensive experiments which illuminated several novel aspects of these viruses.
His discoveries include the vertical transmission of these viruses from one generation of animal to the next; the activation of the viruses by extraneous stimuli, such as radiation; and the role of the immune system of the host animal in preventing the induction of the disease with these viruses.
Dr. Gross also isolated from leukemic mouse extracts a DNA-containing virus capable of inducing parotid tumors in mice. He demonstrated that this virus—which subsequently was designated polyoma virus (PV)—could induce various cancers in the mouse.
The experiments of Dr. Gross, conducted with great persistence despite severe technical difficulties, opened the field of mammalian tumor virology, and laid the foundations for the subsequent discovery by others of cancer-inducing viruses in animals of various species ranging from rodents to the higher primates.
To Dr. Gross, who opposed the prolonged skepticism accorded his findings with tenacious experimentation and insight, and who succeeded in changing the course of medicine, this 1974 Albert Lasker Basic Medical Research Award is given.