Cancer 



Some 50 million Americans living today will be afflicted with 

 cancer and two-thirds of them will die from the disease, if present 

 trends continue. One of every six deaths in the United States is now 

 attributable to cancer, a toll that is exceeded only by deaths from 

 cardiovascular diseases. Almost half of those who die from cancer are 

 less than 65 years of age, with leukemia being the major disease killer 

 of children under 15 years of age. The incidence of cancer and the 

 mortality from it have increased steadily over the last 40 or so years for 

 which statistics on the disease are available. 



The Growing Science Base 



During the same period remarkable progress was made in the 

 understanding of living organisms. Within the overall advances in the 

 biological sciences — to which chemistry and physics made major 

 contributions — were many fundamental advances in biochemistry and 

 its derivatives, such as immunochemistry, cellular genetics, cell 

 biology, molecular biology, and virology. Progress in these areas 

 expanded the knowledge of normal cells, providing new insights and 

 greater understanding of their structure, functioning, and division. 

 Most of this knowledge was acquired through basic research designed 

 primarily to extend the realm of scientific understanding, rather than 

 for its potential applications. 



This understanding, however, provided the basis for elucidating 

 differences between normal and cancerous cells, an essential step in 

 determining the nature of cancer and in developing approaches for 

 preventing and treating the disease. The resulting characterization of 

 cancer is that of uncontrolled proliferation of malignant cells which 

 fail to receive or respond to signals to halt further division. Instead of 

 an orderly distribution of cells in the surrounding tissue, the spatial 

 arrangement of malignant cells appears to be random or haphazard. 

 And in contrast to the spread of normal cells, cancerous cells may 

 become detached from a tumor and move to another site sometimes 

 remote, where a new tumor is started. 



Research over this period also provided insights into the factors 

 which initiate cancer. There appears to be no single cause of the 

 disease — or perhaps more properly, "diseases." Indeed, it is not yet 

 clear whether cancer is a single disease that is manifested in various 

 forms, or many diseases that exhibit similar symptoms. Many factors 

 appear to play an influential role, including heredity and the 

 individual's own metabolic, hormonal, and immunological responses. 

 In addition, man's own acts may be involved in a causal way. Some 80- 

 85 percent of all cancers are estimated to have an environmental cause. 



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