Brussels, 19 Apr 2004
Cancer is one of Europe's biggest killers. New light shed by Swedish scientists on the nature of tumours promises to further our understanding of how this deadly affliction works.
Medical orthodoxy holds that leukaemia, or blood cancer, is triggered by one mechanism and solid tumours – including breast and prostate cancers – are set off by another. Leukaemia normally develops when blood cells that have broken down recombine incorrectly causing normal cells to become renegade cancer cells. At the break or fissure point, loose fragments of genes can bond with so-called fusion genes. This splicing of disparate strands results in what are called fusion proteins.
The majority of cancers, however, are of the solid-tumour variety. It is generally thought that these form as a result of certain cells losing their ability to reproduce identical copies of themselves. This happens when their internal tumour suppressor genes no longer function. Not so, claims a team of Swedish researchers at Lund University. Their research indicates that all forms of non-hereditary cancer (some 90% of cases) are triggered by the same mechanism as leukaemia.
"We now maintain that all [non-hereditary cancers] have the same developmental mechanisms… It is the occurrence of fusion genes and not the lack of tumour suppressor genes that is essential," says Felix Mitelman who heads the research team at Lund University's Section for Clinical Genetics.
The reason this parallel had not been uncovered earlier is technical, the Swedes point out, because it is easier to detect fusion genes and proteins in leukaemia cells. "And if you haven't seen them, you assume that they're not there. But what has been lacking is appropriate methods of examination," Mitelman explains.
The Swedes are hopeful that their findings – if correct – may point the way to novel treatments for tumorous cancers. There is already an effective and mild medicine that specifically targets the active fusion in protein in some forms of leukaemia, the team say, and there is no reason why similar medication cannot be developed for tumours.
However, they acknowledge that the potentially enormous variety of fusions might make it unfeasible to develop such treatments. "Small groups of patients are not of interest to pharmaceutical companies," notes Mitelman. "On the other hand, it may be that several fusion proteins have common traits that makes it possible to use the same drug to combat them."
Cancer is one of the biggest challenges facing the medical profession. In the EU alone, over 1.5 million new cases are diagnosed each year. However, research is paying off. Although the number of cases being diagnosed is on the rise, the number of people dying of cancer in Europe is on the decline, recent studies suggest. Deaths from stomach cancers, in particular, have been halved.
To promote public understanding of cancer, the EU's Train Against Cancer set off from Paris on a tour of Europe on 30 March. Cancer is among the EU's top research priorities. The Union's Sixth Framework Programme for Research (FP6) has dedicated some €435 million to research projects in this field. FP6's main objective is to develop improved patient-oriented strategies via better prevention methods, more effective and earlier diagnosis and more efficient treatment options.