Researchers have made significant progress in understanding the biology of pancreatic tumor, suggesting that there may be ways to identify it before it becomes deadly. The main conclusion is that pancreatic tumors are aggressive cancers. On the contrary, they grow slowly, having to take several years to become fatal. This creates an opportunity to detect and eliminate the cancer at an early stage. Today is diagnosed too late, when a patient has an average of only two years of life and the cancer has already spread to other tissues of the pancreas.
The new developments reported in the journal Nature, were made by two cooperating groups, one led by Shinichi Yach and Christine Iacobuzio-Donahue at Johns Hopkins Medical Institutions in Baltimore, and the other by Peter Campbell and Andrew Futreal at the Institute Sanger near Cambridge, England. Both teams used a new method for decoding DNA very rapidly. This means that instead of studying one gene at a time, researchers can now afford to look through the genome, the monitoring of all mutations that occur in cancer cells.
The Johns Hopkins team was able to identify a long series of mutations that had accumulated in the original tumors of seven patients, as well as secondary cancers that had spread from the pancreas to the liver, lung, and peritoneum, the membrane that lines the abdominal cavity.
Turns out, at least 10 years elapse between the first cancer cell and the appearance within the tumor, the first cell with the ability to spread to other tissues, a process known as metastasis. At least five years are required for the cell to develop the ability to metastasize.
Both the Johns Hopkins team and the Sanger group are now looking for specific changes in DNA, which may help diagnose pancreatic tumors. The leading candidate is a gene called KRAS (pronounced Kay-Rass), which participates in the transmission of messages within a cell. “Almost all pancreatic cancers have mutations in the KRAS gene, so it’s an ideal situation from the standpoint of detection,” said Vogelstein.
Scientists at the Sanger Institute have examined the same tumors that the group of Johns Hopkins, in order to reconstruct the biological history of pancreatic tumors. They found that after the initial damage, possibly signaling the KRAS gene, the natural controls of cell division is lost. “That unleashed a flurry of genetic instability,” said Dr. Campbell.