Scientists have identified a biological process that plays a key role in turning healthy cells cancerous.
The long-sought sequence of chemical events may be an important factor in as many as 90 percent of colon cancers _ one of the most common tumors among Americans _ as well as in numerous instances of melanoma, a severe skin malignancy.
"These are landmark findings," said Curtis C. Harris of the National Cancer Institute. In the short term, the discovery likely will make it far easier to detect potential colon cancers early, he said. In the long run, it may lead to drugs that can halt or prevent tumor formation by targeting the newly identified chemical culprits.
The same process also might be involved in other forms of cancer. That possibility is sufficiently promising that "it's worth surveying other tumor types" to see if they share common characteristics with colon cancer and melanoma cells, Harris said.
Two different research teams, reporting in three papers in today's issue of the journal Science, found that unusual activity of an otherwise obscure protein called beta-catenin is a prime reason that normal cells transform themselves into seeds of tumors.
"We believe this is the major initiating event" in the development of colon cancer, said Kenneth Kinzler of Johns Hopkins Oncology Center, a co-author of two of the papers.
A cell becomes cancerous when it accumulates so many errors in its genes that it ceases to behave normally. These mutations can result from inheritance and can be caused by destructive outside agents such as radiation, toxic chemicals or viruses.