A new discovery shows promise in cancer fight. Scientists have managed to draw a map of the genetic changes that turn normal cells in the brain and pancreas into two of the most aggressive cancers: brain tumors and pancreatic cancer. They hope the map may eventually led to the discovery of better treatments, new diagnostic tests and new drugs to cure the disease.

Scientists analyzed huge quantities of genetic information from different tumor samples in an attempt to find the pathways that most patients share. Researchers are trying to identify which genetic alterations cause which cancers. The findings open the door to finding cancer before it has spread, when it can still be cured by means of surgery.

Cancer is a class of diseases in which a group of cells display uncontrolled growth, invasion, and sometimes metastasis. They grow beyond the normal limits, destroy adjacent tissues and sometimes spread to other locations in the body via lymph, or blood. Nearly all types of cancers are caused by abnormalities in the genetic material of the transformed cells.

Three studies, published in the journals Science and Nature, mark a big step forward in cancer research. Scientists led by Johns Hopkins University examined more than 20,000 genes in tumors taken from 24 pancreatic cancer patients and 22 patients with the most dangerous brain tumor, called glioblastoma multiforme. The third study, which was conducted by a government-funded network of 18 medical centers analyzed 600 genes in glioblastomas from 206 patients.

Scientists had expected to identify a number of key genes that were frequently mutated. But they found a large number of genes that mutated in a smaller part of the tumors.

The good thing is that they found just 12 pathways that were abnormal in most of the tumors.

“It may be more productive to screen for specific pathways, which are a series of successive molecular changes in a cell. This is a very different perspective” from the approach currently taken by most drug companies, Dr. Vogelstein, co-author of the Science study, said.

The genomic analysis found an average of 63 genetic alterations in pancreatic cancer and 12 cellular pathways. The average brain tumor had 60 genetic alterations, researchers found.

The Hopkins team discovered a new gene called IDH1 found in glioblastoma multiforme, a tumor that usually kills patients within a year.

“It is extremely unlikely that drugs which target a single gene like Gleevec will be active against a major fraction of solid tumors. Instead of screening for drugs against single proteins, our work suggests that it may be more productive to screen for drugs that act against core pathways,” said Dr. Bert Vogelstein of Hopkins and the Howard Hughes Medical Institute. Finding drugs that block those pathways will not be easy, Dr. Volgestein added.

Companies already are researching drugs to block a particular enzyme pathway involved in the studies, the Associated Press noted.

The findings mark “a new era in cancer research,” Dr. Victor Velculescu of Johns Hopkins Kimmel Cancer Center said.