Researchers have found dozens of broken, missing and overactive genes that trigger the growth of potentially lethal tumours of the brain and pancreas, a breakthrough which could soon open the door to new treatments.

"The landscape of human cancers is clearly more complex than has been previously appreciated. Fighting it is going to be more of a guerrilla war than a conventional one because there are dozens of mutated genes in each tumour.

Individually, these mutations don't seem formidable. "But working together, they form an enemy that will require us to develop novel strategies to combat them, and the best long-term strategy may be early detection of tumours, when the number of guerrilla warriors is still small and more easily handled," lead researcher Prof Kenneth Kinzler of Johns Hopkins Medical Institutions was quoted by the Daily Mail as saying.

In their study, the researchers split into two groups, decoded the DNA of brain and pancreas tumour cells taken from more than 40 patients.

While one team analysed the DNA of more than 20,000 genes from 24 pancreatic and 22 brain tumours, members of the second team focused on brain cancer and analysed 623 genes from 91 tumours.

The first group found around a dozen chemical pathways in cells which contribute to the development and growth of the cancer. They also found 83 gene mutations actually involved in pancreatic cancer and 42 in glioblastoma.

The second group identified some genes known to cause cancer but whose role had previously been underestimated along with genes not previously known to contribute to the disease.