The Big IF in Cancer

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But by July 1978, as Rauscher surveyed the evidence assembled on his desk, his outlook had changed. New data from Strander, with better controls, were impressive. There were reports by other researchers of positive IF effects on tumors. Cantell had upped his production of interferon, and the evidence accompanying Gutterman's request for $1.5 million to buy IF was persuasive. Rauscher was convinced. He left his office, went upstairs to the A.C.S. executive offices and declared: "It's time to bite the bullet on interferon." The big drive for IF had begun.

In effect, it was like starting an armaments program without fully understanding how the weaponry works. If interferon is the body's Paul Revere, designed to warn against viral invasion and stimulate the defense forces, why does it also appear to work against cancer? Though viruses are suspect in some human cancers, interferon also seems to work against tumors generally thought to be caused by nonviral agents such as radiation and chemicals.

What scientists do know is that IF inhibits the growth of both healthy and abnormal cells by slowing cell division. Unlike most cancer drugs it does not kill malignant cells outright, but it somehow alters them so they stop proliferating. Another important difference: rather than killing cancer cells when they are rapidly dividing, IF works best when they are dormant and in the so-called resting stage. Interferon also seems to issue a call to arms to the general immune system. It marshals macrophages, scavenger cells that gobble up foreign material, and increases both the numbers and activity of another specialized group of lymphocytes, known as natural killer cells. All types of interferon boost the defense system, but the IF produced by T cells may do it best, perhaps because, as Pathologist Robert Friedman of the National Institutes of Health says, it is more of an "insider," a substance tailor-made by the immune system cells themselves. According to Samuel Baron, the Texas virologist, immune IF is 20 times more potent an antitumor agent than the interferon produced by fibroblast or leukocyte cells.

Whatever questions remain about both the role and effectiveness of interferon as a cancer drug, most could be answered if larger amounts of IF were available. Admits Gutterman: "We don't really know what we're doing yet. It happens with every new drug. In its early days penicillin was good at treating minor infections but not the big ones, like endocarditis [a bacterial infection of the heart valves]. It took years to figure out that it would work there too?but only at very high doses. But everyone said at first it would be crazy to try that level. There was just not enough material to work with to find out. The same is true of interferon. It's frustrating."

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