Precancers precede invasive cancers. They are localized changes in tissue lesions - identifiable by their morphologic structure. During carcinogenesis, when normal cells are transformed into cancerous cells, it is possible to identify precancers. Treating or removing precancerous cells at this early stage could prevent the prolonged, painful treatment and deaths of cancer sufferers. According to the authors of the article,
"Premalignant lesions are arguably the most important disease entities of modern man. In theory, the successful treatment of precancers would result in the eradication of most human cancers."
Despite their importance, until now there has been no attempt to produce a list of precancers, or to classify them according to their biological properties. Jules Berman of the National Cancer Institute at the NIH, and Donald Henson of George Washington University, Washington D.C., have produced a first draft of such a classification, which can be downloaded from http://184.108.40.206/jjb/presum.tar.gz. Berman and Henson worked from the National Library of Medicine's Unified Medical Language System (UMLS), extracting all of the terms relating to precancers from the 'Metathesaurus', and adding an additional 10% from their own knowledge. They identified 568 distinct precancer 'concepts', which have been described by over 4700 terms. Often one precancer is described in many different ways, and can have a number of terms that refer to it. The database includes terms from seven languages in addition to English terms.