Chemical world This week
The Top Stones There's very strong evidence that human breast tumors are caused by a virus, according to scientists at Columbia University's Institute of Cancer Research 5 A new weekly information service, Chemical Industry Notes, will be published by Chemical Abstracts Service beginning Dec. 6 7 The chemical industry has plenty of room to increase prices, pay levels, and dividends and still remain within the limits set by Phase II guidelines 10 Plastics industry faces a number of problems as it tries to tackle mounting calls for solid waste disposal 12 Great Britain is on the brink of membership of the European Economic Community, although there are strong critics who oppose the move 16 A New York City-based consultant told a European meeting in Brussels that there's great promise ahead for some of the newer plastics 17 Companies continue efforts to communicate with schools across academic-industrial interface 22 Advances in aliphatic deaminations suggest good reason to believe that these reactions will have importance in future syntheses 28
November 22, 1971
BREAST CANCER VIRUS Despite more than 30 years of research, scientists have not been able to prove conclusively that human cancer is caused by viruses. Strong new experimental evidence from Columbia University's Institute of Cancer Research, however, appears to have brought virologists "as close as one can possibly get" to such proof with present-day limitations, says the institute's director, Dr. Sol Spiegelman. The institute has, he says, for the first time found genetic information from a virus in mouse tumors caused by that virus, and has demonstrated the existence in breast tumors of genetic information partly homologous to that of a known tumor-causing virus. Dr. Spiegelman disclosed his results at an international symposium on breast cancer hosted by the Institute for Medical Research, Camden, N J . Dr. Spiegelman's coworkers in what he termed "the most difficult molecular hybridization experiments we've ever carried out" were Dr. Jeffrey Schlom, Dr. Richard Axel, Dr. Donald Kuse, and Dr. Rudiger Hehlmann. Dr. Spiegelman's group used a reverse transcriptase reaction to prepare tritium-labeled DNA from an RNA virus known to cause mammary tumors in mice. The highly labeled (5000 to 10,000 counts per minute per picomole) DNA was then exhaustively purified and shown to be free of complementary RNA. In control experiments, the group demonstrated that this DNA would not form base-paired DNARNA hybrids with RNA from other viruses or from tissues of noncancerous mice. Such hybrids were formed, hc^vever, when the DNA was mixed with RNA from mouse mammary tumors. The formation of such hybrids, Dr. Spiegelman estimates, requires at least 100 complementary base pairs. There is not enough suspected viral material from humans available to perform a similar experiment, he says, but the next best
thing—"which is, perhaps, even better"—is to challenge extracts from human breast tumors with the mouse virus DNA. Doing so, the group found that 70% of malignant breast tumors gave clear positive evidence of hybrid formation. No response of any sort was obtained when the mouse tumor DNA was challenged with material from other human tumors or from normal tissue. Furthermore, the institute scientists were able to demonstrate that hybrids were formed with RNA from the cell's polysomes—where active synthesis of proteins occurs. It thus seems extremely likely not only that human breast cancer is caused by a virus, but also that the suspected human virus exhibits strong similarities to other mammalian mammary tumor viruses. One immediate implication of this finding is to increase the possibility that anticancer vaccines can be prepared in other species. The Columbia finding also sheds new light on the controversy (C&EN, Sept. 20, page 30) surrounding the identity of the ESP-1 virus isolated from human cancer (Burkitt's lymphoma) cells earlier this year by Dr. Elizabeth S. Priori and Dr. Leon M. Dmochowski. Subsequent investigators have argued Spiegelman:
most difficult experiments
