Responsible care and the Third World.

cytochrome P450 family and the glu-tathione S-transferase-are now well known from both human and animal studies to play an important role in the metabolism of carcinogens. * A better understanding of the potential differences in a tumor suppressor gene pathway in chemically induced and spontaneous kidney cancer. * An understanding of the different capacities of cells for DNA repair. Two types of DNA repair exist: repair pathways and a tolerance mechanism. In repair mechanism , the DNA damage is removed, while tolerance mechanism circumvents the damage without fixing it. * Increased information on the role of viruses in caricinogenesis. For example, recent reports describe how an adenovirus that has a key gene deleted can no longer reproduce itself in normal cells, but does just fine in cancer cells lacking the p53 tumor suppressor gene. As a result, the virus kills the cancer cell, apparently without harming the normal cells. * Advances in our knowledge of signal transduction that have led to major insights into the fundamental pathway that govern growth regulation of cells. These discoveries fulfill the long-sought ability to delineate a sequence of events from extracellular signals to nuclear responses. Additionally, key molecules in the pathway are evolutionarily conserved and mediated in an eclectic array of signals. Alterations in the pathway are important in tumorigenesis and tumor progression. * Discovery that apoptosis-programmed cell death-is highly regulated at the molecular level by oncogenes and anti-oncogenes. Understanding the biochemical and molecular pathway that controls apoptosis is central to the cancer problem. * The characterization of the relationship between peroxisome proliferators and cancer , including the role of cell receptors, DNA oxidation, and gene expression. * A better understanding of the mechanism through which the leukemogen benzene affects bone marrow. Metabolites of ben-zene are found to be highly concentrated in bone marrow of exposed animals. * The elucidation of generic mechanisms of action common to multiple chemicals. These studies have included nitroaromatic compounds, automotive fuels, dioxin, butadiene, chloroform and chlorine, dimethylamine, ethylene oxide, and furans. * Increased expertise in the development of methods for conducting carcinogenic studies, including numerous assays and techniques in a range of disciplines. In 1996, there was evidence of high momentum in both privately funded and government supported research aimed at better understanding risks to human health from exposure to environmental agents. Clearly, environmental health research including risk assessment science is at a remarkable point in time. There …